MOLLUSCA OF INDIA. 123 
Genus Oxyrtss, Pfeiffer. 
This was indicated with its type Manina oaytes, Benson, in section 
vi. of true Helices (without description). The animal of this 
species presents some good characters sufficiently distinctive, and also 
common to other species in the Indian region. It forms therefore a 
good well-marked group, resting on a better basis than many of these 
subgenera. The modification of the mantle-lobes and its very dif- 
ferent dentition mark it as a distinct subgenus. 
Owytes, Pfeiffer, Zeits. Malak. 1856, p. 138 (synopsis of species) ; 
Mon. Hel. vol. iv. (1859) p. 2. 
Hemiplecta, sec. D, Theob. Supp. Cat. p. 22. 
Nanina (Hemiplecta), in part = Owytes, Nevill, Hand-list, p. 46. 
Oxytes, Albers, Heliceen, ed. v. Martens (1860), p. 54; Godwin- 
Austen, J. A. S. B. 1880, p. 157. 
Genus Vanina, sec. Oxvytes, Pfr. ed. Clessin, Nomen. Helic. 1881, 
p. 54. 
Mr. W. Robert’s collection from Darjiling enables me to give a 
fuller account of this genus and its anatomy. 
Description of the Genus. (Plates XXX., XXXI., & XXXII.) 
Animal: tentacles short and rather thickened ; the mucous gland 
or foot-gland with no marked horn above, therefore as in Ariophanta, 
but the slits extending to the sole of the foot. Mantle: the right 
dorsal lobe is, as usual, triangular and well developed (Plate XX XI. 
fig. 2, Plate XXXII. fig. 1 a) ; the left dorsal is in two parts, the 
anterior large, the posterior very small (Plate XXXI. fig. 4, Plate 
XXXIT. figs. 1, 1 a, 16), giving off short tongue-shaped processes, 
right and left or upwards, which may be compared with the similar 
reduced posterior lobe of Macrachlamys atricolor (Plate XXYV. figs. 
3, 4, and 8); the left shell-lobe is a narrow ribbon reflected over 
the peristome ; there is no right shell-lobe. Generative organs: 
the hermaphrodite duct is peculiarly long, and composed above of 
two distinct ducts (Plate XXXII. fig.5,? the g¢ and 2); the male 
organ has a short spindle-shaped fallen « (fig. 56) with a large 
coiled cecum where the retractor muscle is given off, and which may 
be a sort of secretory sac for the development of the spermatophore; 
the amatorial organ is present. The odontophore: this is very 
characteristic ; the central teeth are long, straight, with no side cusps, 
or these are just indicated ; the laterals are also simple, straight, 
unicuspid teeth; the jaw thas the central projection ; the radula 
and foot-gland in this genus assimilate with those of Ariophanta on 
one side, the left dorsal lobes to Macrochlamys (as seen in atricolor 
only) on "the other. 
Shell. Generally of large size, perforate or openly umbilicated, 
dextral, somewhat depressed above, rounded below, some sharply 
keeled ; whorls regularly wound, sides flat above, suture linear or 
very shallow. 
