Helicarion permolle Stoliczka, 1873
“The rather strongy elevated spire, and the membranaceous and transparent structure of the shell, separate this species from the numerous allied forms of the Philippines.” (Stoliczka, 1873)
“Helicarion permolle from Penang Hill is described in the Journal of the Asiatic Society of Bengal, 1873, vol. xlii, pt. ii, p. 18, pi. i, fig. 11 (shell); pi. ii, figs. 21-3 (radula and generative organs). It will be seen that all these characters differ considerably from those of the Perak mollusc, which belongs, in fact, to a different sub-family, the Durgellinae. The character of the anatomy of H. permolle approaches that of Sitala. Stoliczka says of the shell “ad basin striis spiralibus sub-obsoletis notata” and also "the rather strongly elevated spire and membranaceous transparent structure of the shell separate this species from the numerous allied forms of the Philippines." H. permolle, Stol., is included by Mr. Collinge in his paper on the mollusca collected by the " Skeat Expedition" in the Malay Peninsula (Journ. Malacology, 1902, vol. iv, p. 73); hab., Gunong Inas, 3000 feet, State of Perak. It was not figured or described. Mr. Collinge says, "This is certainly the mollusc described by Stoliczka, for both externally and internally it agrees with his descriptions and figures." Some mixing of species in submitting them to the British Museum must have occurred. The animal named H. permolle, which I now describe, cannot possibly be the same Mr. Collinge examined and catalogued. Compare the radula figured by Stoliczka of H. permolle, with the central and admedian teeth on quadrate plates, and that of the specimen I received from Mr. E. A. Smith, with its very numerous and similar teeth on very narrow plates, showing generic differences. The shell and genitalia also differ in the two species. Further, in order to clear up the doubt hanging over the distribution of the Penang shell H. permolle, with the kind assistance of Dr. S. F. Harmer and Mr. C. L. Boulenger I have been able to examine the specimens under that name in the Cambridge Museum. The tube contained the right number of specimens, but they represented three species. (a) One specimen similar to those in the Natural History Museum (Leptodontarion). (b) Three specimens which I feel sure from the form of the shell represent H. permolle, yet when compared with Stoliczka's figures on pi. i, figs. 11-113, cannot be that shell, although there are many resemblances indicated in Stoliczka's description of the animal. They possibly belong to the same genus. I now put them both provisionally in Sitala. This genus now holds in the Indian region ("Fauna British India" (Mollusca), 1908, p. 225) some twenty-six species, and of the majority nothing is known of their anatomy. In course of time, as our knowledge increases, it is quite evident they will require to be separated into new generic divisions. (c) A shell which much resembles the young of Macrochlamys (?) townsendiana, G.-A. & Nev.” (Collinge, 1903)
Stolizcka (1873) original descriptions on Helicarion permolle – “H. testa depresse inflateque conoidea, tenuissima, fere membranacea, translucente, pallide lutescente, vix perforate, spira ultimo anfractu multo breviore; anfractibus 4.5, rapide accrescentibus, ad suturam simplicem adpressis, nitidism convexiusculis, ultimo inflato, ad peripheriam rotundato, tranversim lente arcuateque striatulo, ad basin striis spiralibus sub-obsoletis notato; aperture lunari, valde oblique, labio albescente, minutissime puncticulato, labro tenuissimo, simplici, ad basin valde recedente, ad marginem interiorem umbilico breviter reflexiusculo.”
“The animal is slender and very long; when fresh the extended foot is three times the longer diameter of the shell, which is then entirely covered by the mantle; but in captivity the shell lobes shrink very rapidly, being reduced to narrow linguiform appendages. Middle of back and of the hind foot whitish or very pale brownish, with a slight pinkish tinge; a broad blackish band runs from each pedicle along the sides of the whole back, and also on the sides of the posterior part of the foot, as far as the terminal gland, which is superseded by a very distinct pointed horn; the dark colour extended down to the pedal row, while a large black spot about the middle of the foot on each side reaches down to the sole; pedicles long, grey; tentacles short and almost white; mantle blackish with small whitish dots. All the four mantle lobes are well developed, the left shell and neck lobes are proportionately somewhat larger than the corresponding right ones, and each of the former has a deep but narrow incision in its lower portion.” (Stoliczka, 1873)
“The jaw is about one mill. broad, quadrant shaped, smooth, without any projection in the centre of the concave edge, like in most other species of the genus. The radula is moderately broad and nearly 2.5 mm long; there are 95 transverse rows and about 121 teeth in each row, all remarkably small and from the tenth tooth they somewhat rapidly decrease in size towards the edges. The centre tooth has two distinct denticles on either side and a third much smaller one nearer to the base; the principal cusp is pointed. On the subsequent teeth the inner denticles disappear first, and gradually altogether, then the lower outer, while the upper outer remains, until at last it equals the principal cusp, so that the outermost teeth become almost regularly, though shortly, bicuspid.” (Stoliczka, 1873)
“The nervous and digestive apparatus agree with that of other Zonitidae, except perhaps that the liver is enormously largely developed. The female portion of the genital system has a long sub-pedunculate receptaculum seminis, branching off at its origin. The vas deferens is very short, passing into a rather widened tube, again somewhat contracted near the base of the penis, which is attached by a special strong muscle. The end of the penis widens very rapidly for a short distance before it joins the hermaphrodite opeing. I have not observed, in two specimens examined, any caecal or calciferous appendages.” (Stoliczka, 1873)
Helicarion permolle – “Diam. maj. 8.4, d. min. 7.4, alt. 6.3; alt. Apert. cum perist. 4, ejusd. Lat. 4.3 mm.” (Stoliczka, 1873)
“…on low bushes or between old vegetable matter on the ground, about 500 feet above the sea, on Penang Hill.” (Stoliczka, 1873)