578 Lt.'Cyolonel H. H. Godwin-Austen on 



the edge of the mantle, on tlie left anterior side. The left 

 dorsal lobe is in two distinctly separate portions, the interval 

 being just to tlie right of and below the left shell-lobe. 



The walls of the branchial cavity are sparsely spotted with 

 pure white, similar to the band o£ the same colou.r which, 

 commencing at the rectum, is continuous in a posterior direc- 

 tion, widening considerably over the heart and kidney, and 

 occupies quite half of the circumference of tiie coil of the 

 visceral sac. 



The radula (PI. XVII. figs. 3, 3 a) has the formula 

 67 . 3 . 9 . 1 . 9 . 3 . 67, or 79 . 1 . 79. The central and 

 admediau teeth have a basal cusp on the outer side, rather 

 distant from the mesocone ; the laterals are evenly bicuspid, 

 gradually becoming so from the tenth transition admedian 

 tooth. The marginals are distinctly serrated belnv the outer 

 cusp (fig. 3 a, 65-79). In this character it agrees with 

 Peltatus hudsonicBy but it is far more defined. In the form of 

 the basal plates, as well as in the form of the teeth, this 

 radula does not recall those we know in the genera of Indian 

 Zonitida3. 



The jaw (PI. XVII. fig. 4) is well arched, with a central 

 projection on a deep concave cutting-edge. 



In the generative organs (PI. XVII. figs. 1, la) the penis 

 has an accessory gland, globose and sessile, situated on the 

 epiphallus about one-third its length from the retractor 

 muscle. The flagellum is short. The spermatheca (sp) is a 

 globose sac at the end of a strong, thick, and long duct. It 

 contained a very perfect spermatophore (PI. XVII. fig. 1), 

 protruding in part, having ruptured the wall of the sac. In 

 fig. 2 this is much enlarged, to show its remarkable detail and 

 the beautiful form of the spiny setting. There are some 

 thirty-five tufts following one side of the flume, made up of 

 elongate branches, each side branch bifid at the extreme point ; 

 where perfect they are arranged in pairs like the antlers of a 

 stag. The form the spines assume varies in an interesting 

 way in different species of the genus. The capsule is very 

 long, and this may be termed the anterior i)art of this organ, 

 the flume the posterior. About the middle (see right-hand 

 side of fig. 2) it may be seen that it is joined by a much 

 thinner tube (see PI. XVII. fig. 2 h, w). Tiiis is of very con- 

 siderable length, and when a spermatophore is removed from 

 the sac it is resting in, the whip-like end is found extending 

 down the duct and has to be drawn out of it. 



