Purchasing Preserved Specimens
by Richard L Howey
If you have a special interest in a particular group of organisms, say sea urchins, then it's easy to select specimens to purchase and, fortunately, you won't ruin your bank account, since, although there are hundreds of species of sea urchins, biological supply houses generally sell no more than six species. With these types of organisms, you sometimes have a choice between fluid-preserved specimens and dried specimens. If you are interested in the tests (shells), plates, spines, and other skeletal structures, as I am, then dried specimens are often quite acceptable. If, however, you want to study the water vascular system or examine the stomach contents to see what they have been feeding on, then you will require fluid—preserved specimens. If you are purchasing dried forms, this makes the selection of species slightly larger, although you may have to settle for only the test in some species or perhaps only the spines in some other species.
Most amateurs, however, maintain a fairly wide range of interest and have special favorites among their collection. I want to use this essay to share some of my favorites with you. Since I have already mentioned sea urchins, let me begin with them. There is a fairly large Pacific sea urchin called Strongylocentrotus franciscanus which grows to 8 inches or more in diameter with the spines. It's spines are especially interesting, since they are composed of lovely reddish-purple crystalline plates that form ringlets up the spine. If you take your thumb and index finger and pull it along the spine from the base to the tip, your fingers slide smoothly. On the other hand, if you try to reverse this process, you immediately meet resistance from all the tiny barbs on the crystal plates.
When we think of sponges, we tend to think of bath sponges (which, fortunately for the sponges, are mostly artificial these days) or we think of rather drab sponges found on the rocks near shores or, for those of us who are landlocked, we think of Spongilla, a freshwater sponge. However, for anyone who scuba dives, he or she knows that the variety of form and color of sponges is simply astonishing, breathtaking. However, the sponge which is my favorite is not one which the ordinary diver is likely to encounter. It is Euplectella aspergillium and occurs at depths of from 1,000 to 15,000 feet. It belongs to a group called the hexactinellids or glass sponges. Euplectella is also known as the Venus Flower Basket and is one of the great prizes of my collection. The skeleton is about 8 inches long and composed primarily of silica (thus the name "glass sponge"). In Japan, a charming marriage tradition is associated with this sponge—the couple is presented with such a sponge as a symbol of their eternal bonds, since inside the sponge are the remains of a pair of small shrimp that entered as tiny larvae. As they grew, they became too large to leave the sponge, but their tiny larval offspring could still swim out and seek out new sponges to set up housekeeping. A Western cynic, H.L. Mencken perhaps, might dismiss this as Oriental romanticism while allowing for a different symbolic interpretation—namely, that such a sponge and its inhabitants represent marriage as a prison—"until death do us part." As you can imagine, obtaining these sponges from the depths is no easy matter and as, as a consequence, they are not inexpensive, but are nonetheless a worthwhile investment in a natural history object of superb beauty.
While only a half a dozen or so species of starfish are commercially available preserved in fluid, there are probably 3 or 4 times as many available dried. These creatures are always fascinating and occur in enormous variety. I particularly like the bat star, the leather star, and the crown-of-thorns. I don't know how the bat star got its name; however, since the arms are not distinct and separate, but "webbed", that may explain it or perhaps they have some remarkable way of moving though the water—I simply don't know; I've never observed a live one. The leather star does have a thick integument on its surface which gives it a leathery texture and the crown-of-thorns does, of course, involve a symbolic religious reference as well as being descriptive. I had never seen one of these remarkable creatures until a few months ago when I ordered a couple of dried specimens. Even dried, they are impressive animals and not ones that any creature with half a brain would be tempted to take a bite out of. These creatures are fully armored and have very few predators. In the last decade and a half, the crown-of-thorns inexplicably underwent a population explosion and destroyed large areas of coral reef in the South Pacific and most notably along sections of the Great Barrier Reef of Australia. Life has an extraordinary tenacity and again and again one encounters remarkable examples of defensive and offensive strategies for survival. The crown-of-thorns is not only replete with spines, but these spines contain a toxin which can be a danger to divers who try to remove the starfish to save parts of the reef.
Occasionally you may find another interesting echinoderm in shops that sell dried marine life and that is a large serpent or brittle star which can have arms 6 inches or more long. I was lucky enough years ago to acquire a few preserved in fluid and they have marvelous patterns.
When it comes to sea shells, the list can very quickly get very long indeed. There are two that are particular favorites of mine for structural as well as aesthetic reasons—the nautilus and the Venus' comb murex. Any naturalist who wants to create a cabinet of curiosities should have a nautilus which has been sawed (sawn?) in half to reveal the elegant spiral arrangement of the chambers. With the Venus' comb, the elegance is on the outside rather than the inside and all the delicate spines create a graceful sweep as though the animal had once had an internal skeleton and then been turned inside out.
While we're on the subject of shells, let me move from the macro-world to the micro-world. You can purchase a small vial of radiolaria shells for about $15 from a biological supply house and you get a thin glass tube with what looks to be about a half an inch of sand in liquid at the boom and you will be furious and curse me. But, before you put a curse on me, take a micro—pipet and put a tiny drop of the sediment on a slide and look it with a low power on your compound microscope. Now you will not only not want to curse me, you will want to shower me with rare gifts and large sums of money. No? Well, O.K., but you will have to admit that the radiolaria shells are spectacular. What is wonderful about micro-shells is that an extremely small sample contains thousands of specimens. This is also true for foraminifera or forams, but they are more difficult to obtain from biological supply houses for some unknown reason. (I have very small vials of quite remarkable deep sea fossil forams from the Indian Ocean which I will soon be selling through an advertisement. If you are interested you can keep an eye out or send me an e-mail inquiry at email@example.com and I will provide further information. The samples are difficult to obtain and rare and, as a consequence they are not inexpensive.)
Other types of shells which should be in every microscopist's collection are diatom shells which again are predominately silica and come in a great variety of forms and sizes. Diatoms have long been favorite objects for the microscopist, not only because of their intrinsic beauty, but for a very practical reason as well. The sculpturing of the surface often looks like intricate patterns of lines which in reality consist of tiny dots. Consequently, certain species of diatoms have been singled out as ideal objects for testing the resolving power of lenses. There are some diatoms whose patterns are so fine that only the most expensive and finely made objectives can resolve them. Test slides containing several species, each with finer detail can be purchased from biological supply houses or from Klaus Kemp.
Victorian microscopists were so enraptured by the elegance of these shells that they devoted enormous time and effort to creating elaborate arrangements of diatom shells as exhibition slides. The diatoms were arranged in circular patterns, as rosettes, and in a variety of variations. Some contained 25 diatoms, some 50, some 100 and I have a vague recollection of hearing of a slide consisting of an arrangement of 1,000 diatoms! In any case, these slides can be spectacular and I have one which I purchased several years ago which, although it only has 25 diatoms, is quite a splendid arrangement. Fortunately, this tradition has not been lost as there are people, often anonymous, who do such arrangements for supply houses, and there is also Klaus Kemp whose skill every bit matches that of the Victorian diatom slide makers. Through the generosity of kind friends, I have been given two of Mr. Kemp's slides as gifts and I am very much impressed by the singular high quality of his work.
In the micro-world another favorite of mine is desmids. These do not have either a calcium carbonate shell like the forams or a silica shell like radiolaria and diatoms, so they must be studied either alive or preserved in fluid.
A step up into the macro-world brings us to the extraordinary alga Acetabularia which, depending upon your sensibilities, looks like either a miniature umbrella or a very small mushroom and, in fact, after a rainy day, I have found tiny mushrooms that quite resemble Acetabularia. The little umbrella is about ½ to ¾ of an inch in diameter and the stalk may be 2 inches or so in length. Quite remarkably, this is a singe giant cell.
Butterflies, beetles, and moths are, like shells, dangerous categories, especially for addictive personalities such as myself. It's probably a good thing that I've never made very much money, otherwise I should need a separate laboratory building, a warehouse for storing specimens, and a team of assistants. Butterfly and moth wings with their elegant patterns of scales are deeply absorbing objects of study, as are the feathery antennae, the mouth parts, and the eggs if you're lucky enough to find some. These days you can actually buy butterfly eggs from butterfly farms and raise your own. Whenever I find a dead butterfly or moth, I try to collect it for examination and it's important not to let yourself be misled by a dull color or missing parts. You will probably be cutting off sections to look at anyway and sometimes I have found specimens which look so drab and bedraggled, that they hardly seemed worth an effort—but, those same drab specimens, when placed under the microscope, may possess a beautifully intricate variety of scales and minute hairs. If you are reluctant to go out in the field collecting with net and poison jar, then examine the grille of your car, especially after a trip on the highway. It is likely that you will find an assortment of butterfly wings, beetles, and flies. The ordinary mortal would treat this debris with contempt, but for the amateur naturalist, it is a miniature treasure trove.
Sometimes at yard sales, one can also discover insect treasures and they often come in the form of kitsch—for example, butterfly and dried flower arrangements in glass plaques for wall mounting or the more ambitious three-dimensional arrangements under glass or plastic domes. During one summer, I found one dome mount (plastic) and one square box (glass) mount of the exquisite Brooke's Rajah Birdwing butterfly. The dome had one specimen, the box two. For the two mounts, I paid at most $5.00. At biological supply houses, you can easily pay over $50.00 for a single unmounted specimen of this butterfly! At the price I paid, one can easily afford to sacrifice one specimen for study, but these butterflies are a remarkably beautiful contrast of iridescent green and stark black. I bought them about 10 years ago, and to be honest, have not yet brought myself to sacrifice one for detailed examination. However, I shall soon—maybe.
Beetles—why have I always been so attracted to these little armored critters—scurrying or lumbering—they remind me a bit of tanks. They range in size from ones so tiny they must be observed under the microscope to the Goliath beetle which can reach a length of 5 inches or more. Beetles have an amazing repertoire of defenses from the heavy armor and horns of the rhinoceros beetles to the burning spray of the multi-colored, iridescent blister beetles. Some of them are so strikingly colored that they look like Juan Miro had painted them in his studio.
In a pasture or on the prairie, one frequently finds dried flat cakes of cow dung and, if you turn one over with a stick, you may find one of nature's cleanup crews busily at work—dung beetles.
While we're considering armor, let's talk abut two other remarkable creatures and ,for this, we have to return to the sea. The first is the extraordinary living fossil—the horseshoe crab (Limulus) which is not a true crab and faintly resembles a giant trilobite. These bizarre creatures can reach a length of well over a foot (including the tail) and they lumber up on shore to mate and lay eggs. In spite of their formidable appearance, they are quite harmless, and, as it turns out, a very valuable resource for certain kinds of medical research. A Limulus or two make a fine addition to anyone's cabinet of curiosities, but in collecting specimens, we have a profound obligation to be sure that we never take more than we can really use, and that we never remove any endangered organisms from their environments. There are some creatures where survival is threatened by over-collecting, but two far greater dangers to all kinds of sea life are oil spills and pollution from fertilizers, other chemicals, and nuclear waste.
Take a dried or preserved horseshoe crab and observe the remarkable carapace, the multiple eyes, and the spike of a tail. Turn it over and notice how thick the armor is at the anterior end. On the underside you can see the legs and the gills and if you have a fluid-preserved specimen, you may even find specimens of a flatworm which is a commensal on the gills. This is a creature built for survival and, survive it has, virtually unchanged for millions of years.
The other armored creature which I want to mention is a small fish—the specimens I have are 8 to 10 inches in length—its popular name is the bat fish. It is anomalous in several respects: in the first place, its front fins are modified into leg-like appendages and it "walks" around on the bottom of its hunting grounds; secondly, it is a type of angler fish and has a small rod-like structure that projects from its forehead and, at the end of the rod, is a small blob of tissue that looks like a morsel of food. The bat fish dangles this "morsel" and wiggles it to attract potential prey—the irony of it—a fish fishing and long before there were ever fishermen. The third remarkable feature of the bat fish is its modified scales which are imbedded in the skin like small pieces of coral.
Another sort of extraordinarily modified relative of fish is Narcine brasiliensis or the famous electric ray. These creatures can generate an electrical shock that they use to stun their prey. The electrical potential is generated by stacks of calcareous plates in the "wings" of the ray. The collections of plates act like storage batteries and when the ray feels threatened or is hunting prey, it can discharge these, releasing a powerful shock of up to 200 volts..
The next item I'm going to mention, some of you will find repugnant—owl pellets. Owls capture field mice and other rodents and the occasional bird and gulp them down, which presents something of a problem for them in terms of dealing with all the hair and the bones, a problem which they have solved in an ingenious fashion. After powerful digestive fluids have dissolved out the material utilizable as food, the hair, teeth, bones, and other indigestible parts are formed into a pellet which the owl regurgitates or, to put it more graphically, vomits up. One can sometimes find such pellets in the vicinity of a nesting area and, yes, they are of sufficient interest that they can also be purchased from scientific supply houses.
There is something rather splendidly eccentric about naturalists that can lead a scientific supply house to devote an entire page to owl pellets and paraphernalia related to the examination thereof. Personally, I think this is a wonderful phenomenon and so I'm going to ramble on about it for a bit in case you want to jump ahead to the end and find out whodunit (it was the butler).
My attitude toward all of this is rather complicated; I find it wonderful—slightly amusing—touching, but mostly wonderful, that a company would devote an entire page of its catalog to owl pellets and accessories. So, please don't take any of the following remarks as mocking—gently, ironic perhaps, but in no way, mocking.
For starters, I think it's terrific that one finds a listing in the index which reads "Owl Pellets—p. 190". Who'd have thought it? I turn to page 190 "and what to my wondering eyes should appear, but"1) Owl PelletsIsn't this amazing! Sometimes, with luck and patience, one can reconstruct the entire skeleton of a prey animal. The charts and posters which are available are very helpful in identifying bones and teeth and make this a fascinating investigation. For the curious amateur, a good place to begin is with the Individual Student Kit which has an I.D. sheet, a magnifier, 3 owl pellets and several other helpful items and, if you get sufficiently intrigued, you can buy additional owl pellets for only $2.00 each.
2) Owl Pellet Investigation Classroom Kit
3) Individual Student Kit
4) Advanced Owl Pellet Kit
5) Wooden Probes "For dissection of owl pellets"
6) Ecology and The Barn Owl Video
7) Bone I.D. and Food Web Posters
8) Dissection Charts and Overhead Transparencies
I want to quote a paragraph from the catalog under the Owl Pellet section:
"Our Barn Owl pellets have been inspected and approved by the U.S. Department of Agriculture. All our owl pellets are handled and treated over and above their strict guidelines of 72°C. (128°F.) for 30 minutes. Our pellets are heated to 150°C. (300°F.) for 1-2 hours."
At first blush, it's hard to read this with a straight face. What's the Department of Agriculture doing mucking about with owl pellets? Furthermore, the company's description of how they exceed the U.S.D.A.'s strict standards creates the impression that if you order enough owl pellets, you'll eventually get a free casserole recipe booklet.
Now, I am just teasing a bit, because there is a serious issue here. The prey of owls—mice, gophers, voles, moles, shrews, and birds can carry mites, ticks, and fleas, and, in the rodents' hair and remnants of dung, there can be fungal spores, pollen, bacterial spores, and virus particles. In the last decade, the presence of hanta virus in deer mice and other rodents, particularly in the southwestern U.S., has created an increasing public health concern. Since small rodents are a staple in the diet of many owls, there is the possibility that untreated pellets could be vectors for the virus. So, fortunately, my old friends at Cynmar (whose catalog I have been quoting—see endnote) sell only owl pellets that have been rigorously sterilized well beyond government requirements.
Let me conclude with a few sentences about another kind of specimen that has much more aesthetic appeal than owl pellets, namely, feathers. Feathers are another one of nature's underrated marvels and the evolution of feathers is itself a fascinating chapter of natural history. We rather tend to take them for granted, although we may exclaim when we see a brilliantly-colored feather of a wood duck, or a parrot or peacock. But, you really haven't seen a feather until you observe it under a dissecting microscope. From a purely structural point of view, they are astonishing; the ribbing, the struts, the barbules—and the intricate fashion in which all of these elements fit together in a dynamic fashion to facilitate flight.
If you hunt or have friends who hunt birds, then you can readily build up a nice collection of feathers. In Wyoming, many of my students go hunting and occasionally, I'll ask one to bring me some feathers. On several occasions, when I have inquired after the feathers, I discovered that the students decided to keep them for themselves having not noticed previously just how beautiful they are, and even though I didn't get the feathers, that pleased me.
My father used to go pheasant hunting and now he just gardens a bit, but I think that in some strangely osmotic way, he got me interested in feathers. Oh, yes, I too went hunting as a boy. I walked miles and miles of corn rows and hedges, but never got a pheasant, which made it seem rather tedious at the time. Eventually, to my relief, my father stopped asking me to go along—I think he and his friends had concluded that I was something of a jinx.
Pheasants were, of course, imported from China where there were special breeds reserved for the emperors. These feathers are striking under the microscope and one can spend many hours studying them. Another one of my favorites is the feathers of ducks, wood ducks in particular. I am sure that there are extraordinary feathers belonging to rare and exotic birds, but they are rarely available. One kind that is available is peacock feathers and extraordinary they are! We have had a few peacock feathers around for many years; we used to buy them to play with our cats. However, it was only a couple of years ago that it occurred to me to look at one under the microscope—stunning! So, go buy 10 peacock feathers for your cats and 2 for you; they're cheaper by the dozen, and after your cats get bored with them (this usually occurs sometime between 3 minutes and 3 days after they are presented with them), you can take the tattered shreds and make some excellent slides. From butterfly wings and feathers, you will quickly learn that some colors in nature are the result of pigments, whereas others are purely structural and result from the refraction of light. In those areas where the color is a consequence of structure, you can change the angle of illumination and observe how the color shifts.
And minerals! I haven't said anything about minerals, but this essay's already too long, so I'll save them for another occasion.
Comments to the author Comments to the author sent via our contacts page quoting page url plus : ('rhowey','')">Richard Howey welcomed.
The specific prices which I have cited here are from the 2000-2001 Scientific Equipment Catalog of Cynmar Corporation, 21709 Route 4 North, P.O. Box 530, Carlinville, Illinois 62626; Telephone 1-800-223-3517; FAX 1-800-754-5154; E-Mail: firstname.lastname@example.org; Website: www.cynmar.com. I have no affiliation whatsoever with Cynmar except as a customer and I receive no financial benefit from citing them. I use them as an example, because they are a modest-sized supply house with a reasonable variety of apparatus, items that are mostly of very good quality and lots of owl pellets. I have made eccentric requests for them to find items not in their catalog and they still put up with me. The three main reasons I have used Cynmar as an example are: 1) they have owl pellets, 2) I have gotten good quality items at prices well below the large supply houses and 3) the people are friendly, courteous, and exceptionally helpful and, in a world that seems to be working harder and harder to depersonalize us by treating us as a collection of identification numbers and credentials, I find the human touch very appealing.
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