One more 19th century painting of a terrestrial gastropod and a malacologist's story

This picture of the snail formerly known as Helix aspersa adorns the cover of M. S. Lovell's 1867 book The edible mollusks of Great Britain and Ireland with recipes for cooking them. The book is available at the Biodiversity Heritage Library. I have scrolled thru the book quickly and noticed, in addition to recipes, many records, natural history observations and other miscellanea related to edible mollusks and also 12 colored plates.

The following anecdote is from page 20 and was taken from the famous 19th century malacologist E. A. Rossmässler's Reise-Erinnerungen aus Spanien.

Much amusement was afforded to the Spaniards, by Rossmässler throwing away the delicate animal, and only retaining its shell, which to them was worthless, but most valuable to him as a conchologist. Upon one occasion, on arriving at a posada, he found the hotel people sitting down to their midday meal, before a great dish full of snails. He says:—"One look satisfied me that they were of a rare kind, for which I had sought in vain; and I immediately seized upon some of the empty shells, which caused a universal laugh.

To a modern malacologist the snails' bodies would be as valuable as their shells. Rossmässler would undoubtedly have done the future malacologists a great favor if he had saved a snail or two along with their shells.

The previous 19th century painting of terrestrial gastropods was here.

The Aqueduct of Vallonia

This is the Alexandria Aqueduct, or what is left of it, in Georgetown, Washington, D.C. According to Mike High's The C&O Canal Companion (1997), the aqueduct once connected the C&O Canal to another canal (not named in the book) on the Virginia side across the Potomac River, which is visible on the right (the Key Bridge is in the background). The C&O Canal is towards the left of the aqueduct in this picture.

I was there last Friday. I noticed that parts of the walls of the aqueduct were wet from water seeping out from between the rock blocks (it had rained the day before). A close inspection revealed tiny snails crawling on a section of the wet wall partially covered with red ivies (towards the lower left in the photo). A closer inspection revealed that the tiny snails were Vallonia.


They are either Vallonia pulchella or V. excentrica, the 2 being somewhat hard to distinguish. Their shell diameter is ~2.3 mm.

The next time I am there I will check again to see if the snails are always out on the wall.

Bipalium adventitium — Part 4

In part 3 of this series, I attempted to feed a slug, Megapallifera mutabilis, to my "pet" planarian Bipalium adventitium. The planarian refused. In the comments, Megan P. suggested that I repeat the experiment with baby slugs. You see, as long as it is in the name of science, we can even feed babies to predators. We are collecting data here.

I thought Megan's idea was worth a try, but I was freshly out of baby slugs. Luckily, Megan had some and was willing to part with a few. So, last Thursday I visited her lab at the University of MD and returned home with 3 juvenile Philomycus carolinianus, another native species in our favorite slug family the Philomycidae. And early this evening, I offered them to El Depredador that had been waiting patiently in the basement.

So far the slugs have survived. But the night is young and there is plenty of time for a surprise pharynx eversion.

To be continued.

Fluid trends

In the previous post in this series, the index of satisfaction (IS = optimism / happiness) had stabilized for a change. However, the most recent data clearly demonstrate that the long term trends are fraught with uncertainty.

A sharp drop followed by a gradual recovery was nobody's guess. And once again, we don't know if it's optimism that's going thru a turbulent period or happiness is fluctuating depending on the amount of wine intake.

I will continue to monitor this crucial index and provide updates.

How about a long penis covered with spikes?

The arrow is pointing at the pointed papillae covering the penis of Chondrus tournefortianus. I don't know what function the papillae may have.
The picture shows the everted penis of the land snail Chondrus tournefortianus. This hapless pair was mating on a hillside at the outskirts of the city of Kastamonu, Turkey one cold and wet morning in October 2008 when I chanced upon them. Not only did I intrude upon their privacy by photographing them, but I also pulled them apart to see if their mating was anatomically reciprocal.

Remember that pulmonate snails, and that is what these are, carry both male and female; in other words, they are hermaphrodites. Therefore, when they mate, it is possible for each snail in a pair to use its penis to inseminate its partner. In many snail species, mating is indeed anatomically reciprocal*. But in some species only one snail acts as the male and gets to inseminate its partner.

One way to determine if the mating of a pair is anatomically reciprocal is to kill them in copula and then to dissect them. I don’t particularly like killing snails, especially if they are in the process of performing a fundamental evolutionary act, that is, passing on their genes. So instead, I pull them apart while watching them under a microscope or a magnifying glass, if I am in the field, and hoping to see their penises as they are being withdrawn (more about that technique here). Other than one interrupted coitus, no damage is done.

In the case of this particular pair of Chondrus tournefortianus, after I separated them, I saw the penis of only one snail and, therefore, concluded that their mating was anatomically unilateral. The details of this lucky encounter and how it has contributed to our knowledge (or the lack thereof) of the family Enidae, to which this species belongs, have just been published in a short paper of mine in the journal Zoology in the Middle East. You may read it here. The paper also has a photo of the mating snails before I took the matter into my hands.


*Strictly speaking, anatomical reciprocity doesn’t necessarily mean reciprocal insemination; an individual could mate without contributing sperm. Anatomical reciprocity can also be simultaneous or sequential. Yes, I know, it does get complicated.

Another 19th century painting of terrestrial gastropods

This is Tafel XI from an 1889 paper by E. von Martens*. The drawing of the live snail on the bottom represents a Helix asemnis venusta, a species of southwestern Turkey and the nearby Greek Islands.


The previous 19th century painting of terrestrial gastropods was here.


*E. von Martens. 1889. Griechische Mollusken. Archiv für Naturgeschichte 55:169. (Full text from the Biodiversity Heritage Library.)

A true confession: I was Otto Mann

The magazine American Rationalist praises itself for being an "Alternative to Superstition and Nonsense" for over 50 years. I subscribed to it for several years in the 1990s. Then I got tired of it, although I don't quite remember why, and ended my subscription.

However, I did publish one article in the AR. It came out in the November-December 1993 issue. It was titled Life, Death and Mind Transfer and was about, well, life, death and mind transfer.

Recently, I read again what I had written and quite liked it. Although, I admit, there isn't much in it that was original—at least it seems that way to me now, almost 17 years later. Mind transfer has been a favorite subject of many a science fiction story.

Nevertheless, I decided to scan it and upload it to my library for all to read. Here it is.

The funny thing about this article is that I published it under the pseudonym Otto Mann, although, again, I don't quite remember why. If anyone doubts that I was Otto Mann, I do have a short note to that effect from the late Gordon Stein, the then editor of AR. I also cite one of my own papers for whatever it may be worth.

A few years later I published another article somewhere else as Otto Mann. I will put that up some other time.

Bootleg proceedings of the 3rd OVUM meeting

The 3rd annual meeting of the Ohio (River) Valley Unified Malacologists (OVUM), organized by Tim Pearce, took place at the Carnegie Museum of Natural History in Pittsburgh yesterday. There were 14 participants and 11 presentations. Here are the speakers and very brief summaries of what I thought they talked about in the order of presentation.

Charlie Sturm (CMNH): Ongoing attempts to locate the field notes that were associated with the freshwater mollusk collection of Herman P. Wright that was donated to the Carnegie Museum in 1932 and which has since been sitting uncatalogued in a drawer.

Tim Pearce (CMNH): Studies to correlate the weather data with the short-term movements of snails.

Francisco Borrero (Cincinnati Museum of Natural History): taphonomic evidence for turnover in the freshwater mussel community in the Ohio Brush Creek.

Aydin Örstan (CMNH): Results of the survey done to determine the present range of Cepaea nemoralis in Frederick County, MD that was introduced by the late Wayne Grimm in 1969.

Andrew Turner (Clarion University): Elevated pH, caused by nutrient enrichment (increased phosphorus levels), may interfere with the freshwater gastropods' detection of the chemical cues produced by their predators.

Beth Meyer (Western Pennsylvania Conservancy): Mussel, fish and macroinverterbate survey of the French Creek, PA.

Nevin Melte (WPC): Recent PA Fish and Boat Commission activities related to mussels. These included the collection and relocation of a large number of mussels from behind Carter’s Dam prior to its removal.

Emily Cholak (Clarion University): Effect of predation risk induced by fish and crayfish on the population dynamics of their prey, the freshwater gastropod Helisoma trivolvis.

Kip Brady (New Philadelphia High School): Ecological projects involving freshwater gastropods in high school biology classes. Will the students develop a better appreciation of wildlife?

Tim Pearce (CMNH): Laboratory experiments to determine if the slug Philomycus carolinianus likes to aggregate with its conspecifics?

Aaron Stoler (University of Pittsburgh): How the presence of leaves from different species of trees in the water affect the survival of tadpoles and the gastropods Physa acuta and Helisoma trivolvis.

T. rex was there too.