Description of a new California Helix, with notes on others already described.
BY J. G. COOPER, M.D.
Helix (Arianta) sequoicola, Cooper.
Sp. Ch. H. testa rotundata, umbilicata, spira depressa, anfr. ult. nonnunquam subangulata; anfr. vi ad vii et dimidium, perist. obliqua superne parum deflecta; labio tenui, reflexo, infra crassiore, acuta. Colore atrobrunnea, vel olivacea, zona nigra, lata, inter duabus ochraceis sita, in spira semicelata, labio albo; intus læte purpureo, zonis duabus albis. Epidermide nitente, infra polita, striis incrementis læve perspicuis, interdum tenuissime malleata, rugis spiralibus; supra punctis piliferis creberrime induta; pilis brevissimis junioris deciduis.
Animal schisto-colore; corpore cylindraceo rugosa, tentaculis longis, pede postice elongata, cuneata.
Testæ lat., major, 0.93 ad 1.20; minor 0.76 ad 0.96; alt. 0.42 ad 0.54 poll. Angl.
Hab. Santa Cruz, California, in ligno carioso, locis humidissimis.
Specific characters. Shell rounded, umbilicate, spire depressed, last whorl sometimes subangulate, whorls 6 to 6½, peristome oblique, little deflected above; labium thin, reflexed, thickest below; acute. Color dark brown or olivaceous, with a broad black band between two yellow ones, half hidden on the spire, lips white; within a fine purple with two white bands. Epidermis shining, polished below, the lines of growth faintly visible, sometimes very lightly malleated, and with spiral ridges; above with crowded scars bearing very short bristles in the young shell which fall off in the adult.
Animal slate colored, body cylindrical, rugose, tentacles moderate; foot elongated, behind wedge-shaped.
Shell—large diameter 0.96 to 1.20; smaller diameter 0.76 to 0.96; height 0.42 to 0.54 hundredths of an inch.
Hab. Santa Cruz, Cal., among decayed trees in the dampest places.
This beautiful species is quite rare, only three adult and twelve young specimens having been found after long searching. It will probably occur more commonly in some part of the redwood forests which I have been unable to explore. It approaches nearest to H. Dupetithouarsi and H. fidelis, being between them in form and size as well as colors, but the pilosity at once distinguishes it. Its distinct bands and rounded whorls separate it from H. infumata and Hillebrandii, the latter when perfect having also much longer hairs. The animal is lighter colored than those of H. arrosa, Nickliniana, redimita, ramentosa, tudiculata, (which are all very similar) but much darker than that of Dupetithouarsi, and I believe also of fidelis and infumata. The form of the shell is a link connecting these with Mormonum.
In the tabular arrangement adopted in my State Survey Report, it would come in as the pilose analogue of H. Dupetithouarsi, and H. exarata, which are also its nearest geographical neighbors, as follows:
| § A. Shining; band triple, not rugose, l. whorls 6 to 8. | § B. Dark; hirsute in the young, l. whorls 6 to 6½. | § C. Brown; band single, rugose, sculptured, l. whorls 6 to 7. |
|---|---|---|
| H. fidelis. | H. infumata.[24] | H. arrosa. |
| H. Traskii.[25] | H. sequoicola. | H. exarata. |
| H. Dupetithouarsi. | H. Hillebrandii. | H. Ayresiana. |
Judging from the form of H. Mormonum, it is possible that the young will be found to be hirsute.
The table referred to includes twelve other banded species of California, arranged under the same headings. It is interesting to observe that the § A 1 and B 1 groups inhabit coniferous forests, and probably feed chiefly on fungi found in decaying wood while § C, including also H. Nickliniana, Bridgesii, redimita, ramentosa, tudiculata, Californiensis (and Carpenteri?) are found in woods of oak, etc. Another group which I place in § A (as not being rugose) are found in dry, treeless localities where they seem to represent those last mentioned, the size, form, and number of whorls furnishing parallels, but being usually less in size, as might be expected of species from arid regions, and often with the band single or obscured; these are H. Tryoni[25], rufocincta, Kellettii, crebristriata, Gabbii, facta.[25]
The bandless species, of which there are few on this coast, present analogous sections as to surface characters, and exhibit much greater varieties in the form of their apertures, by which they can be arranged in groups, having a greater development of species in the Atlantic States and more distinguishable by form than by surface.
H. Townsendiana alone approaches § C in its rugose sculpture, but otherwise differs greatly from the usual types of California.
From the shells alone, five subgenera may be established out of the banded group, which I will describe in a future article.
Note.—There is a single specimen of Helix in the State Collection, supposed to have been obtained in the Mount Diablo range by Prof. Brewer, which closely resembles the small form of H. Sequoicola in shape, but being nearly bleached is too imperfect to describe minutely, though very likely a new species.
It is remarkable for having seven whorls, while the former and H. Mormonum of the same size have but six; it is also less compressed than the latter, and the umbilicus is less covered. The color where remaining is shining gamboge yellow (faded?) with a single very narrow band above the middle, not showing the pale band on each side of it that is so marked in others of the group. The sculpture seems to have been very slightly malleated, and with the faint lines of growth cut by smooth depressed waved grooves transversely, and thus obliquely to the sutures (while those of H. Traskii are parallel).
Diam. maj. 0.95; alt. 0.40 inch.
A region so near San Francisco ought to furnish more and better specimens.
There is a form referred to H. fidelis, from Humboldt Bay, which may also prove a new species. It is entirely purplish black, without bands, the lips white inside, and differs from infumata chiefly in great elevation and thicker lips, having even the subcarinate body whorl of the latter, and the same number of whorls (6½). There is, however, no trace of bristle marks, and some specimens appear to connect it with fidelis, suggesting a possibility of its being a hybrid.
The State Collection contains one specimen, obtained from the late Dr. Frick.
Diam. maj. 1.24; min. 1.09; alt. 0.70 inch.
[24] In this the band seems obscured in the general blackness of the shell; occasional varieties of several others are found without the band, as if from disease, as in H. anachoreta.
[25] These species have parallel spiral grooves, not rugæ.