OCR Text |
Show 1 9 0 6 .] OF SOUTHERN INDIA AND CEYLON. 681 radula is essentially the same as in Farran's * specimen, but the median tooth is a little lower and broader and the side-teeth are more distinctly denticulate. Kelaart's specimen is not accompanied by any name or note, but I strongly suspect that it is Diphyllidia marmorata f. His description is vague and the plate, which is very bad, adds nothing to it. But perhaps the living animal might be identified by its coloration. Kelaart says the body (i. e. the sides of the body under the mantle, as the plate shows) is white and spotted ; the mantle yellowish brown and marbled with darker brown or greenish brown; the veil white, with a yellow margin. The colour of L. cinerea in life is unknown. L in g u e l l a variolosa Bergh. (Bergh, Malac. Unters. in Semper's Beisen, Theil vi. Lieferung i. 1904, pp. 21-24.) Five specimens are perhaps referable to this species, which is recorded from China. They represent two well-marked varieties, which may possibly prove to be distinct species, and in all the radula differs slightly from Bergh's description. That description, however, was made from a single specimen, and the differences observed do not appear to exceed the variations possible within the limits of a species. In two specimens (A) the external characters correspond closely with Bergh's description. In two others (B) the dorsal tubercles are much smaller and arranged in continuous ridges, which materially modify the general appearance. The fifth (C), however, stands midway between these groups, and suggests that they are both varieties depending on the size and arrangement of the tubercles. The buccal parts are essentially the same in all. A. The larger of the two specimens is about 43 mm. long and 17 mm. broad. The conformation of the anterior part seems to be as in Linguella, but the portion before the rhinophores is much contracted and bears only a few minute tubercles. The colour is uniform brownish yellow. The back is studded with large and small tubercles, which towards the rhinophores show a tendency to arrange themselves in 5 longitudinal lines. The larger tubercles are as much as 1*5 mm. in diameter, and bear a dark spot or depression in the middle. The branchiae and side-lamellse are as described by Bergh, and behind the branchiae is a globular or ovate body, apparently a modified lamella, measuring about 2'5 mm. by 1 -5 mm. The foot is grooved in front and with small pointed * Farran''s description of the radula is liable to misinterpretation. He says: " The first lateral tooth with 9 denticulations on the outer edge. The teeth increase in length outwards, the number of denticulations decreasing." But the denticles do not decrease from 9 downwards. They attain the number of 18 or 20 before they begin to decrease. f He expressly registers Diphyllidia and Linguella as synonyms under D.formosa. |