. Bulletin - United States National Museum. Science. EASTERN PROVINCE SOUTHERN REGION SPECIES. 357 with 8 laterals. The sixteenth marginal tooth is shown. A specimen from west coast of Florida (H. nemphill) had lG-1-16 teeth, 7 on either side being laterals, all like what I have lignred in Terr. Moll., V, for those of 31. incrnstaia. Fig, 385 a. HEMITROCHtJS, Swainson. Animal heliciform (of H. varians), stont, anteriorly blunt, posteriorly long, acutely-terminating; mantle central, Fig. 386. thin, simple, protected by a shell; no dis- tinct locomotive disk; no caudal mucus pore; respiratory an
. Bulletin - United States National Museum. Science. EASTERN PROVINCE SOUTHERN REGION SPECIES. 357 with 8 laterals. The sixteenth marginal tooth is shown. A specimen from west coast of Florida (H. nemphill) had lG-1-16 teeth, 7 on either side being laterals, all like what I have lignred in Terr. Moll., V, for those of 31. incrnstaia. Fig, 385 a. HEMITROCHtJS, Swainson. Animal heliciform (of H. varians), stont, anteriorly blunt, posteriorly long, acutely-terminating; mantle central, Fig. 386. thin, simple, protected by a shell; no dis- tinct locomotive disk; no caudal mucus pore; respiratory and anal orifices snbcen- tral, on the right side of the mantle, under the peristome of the sliell, generative ori- Animal oih. varians. fice not observed, probably behind the right eye-peduncle. Shell external, with the perforation open or closed, globose, shining; spire short; whorls 4-5, the last large, deflexed at the aperture; colu- mella dilated at the base; aperture contracted, subvertical, roundly lunate; peristome simple, obtuse, labiate within, its margins distant. A West Indian genus; one species has been introduced into the Florida Subregion. • In Ann. Lye. iST. H. of IS". Y., X, 341, I have, in connection with my friend Mr. Bland, shown the necessity of using this name in preference to Folymita. I will here simply repeat that the type of the latter genus is muscarum, Lea, from which the other species formerly associ- ated with it differ generically in dentition. They will therefore be known bj" the first published name, Hemitrochus. The jaw is strongly arched, with acuminated ends, smooth anterior Fig. 387. surface, and decided median prominence to cutting margin. Fig. 387 represents the jaw of rarians. The other West Indian species examined by me have the same type of jaw, excepting H. 31illeri, which has one short median rib. The lingual membrane (Terr. Moll., V, Plate IV, Fig. L) has about 32-1-32 teeth ; another specimen gave 43-1-43 teeth, with 17 pe
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