290 MR. GUY C. EOBSON ON MOLLUSCA 



4. Xesta CITKINA (Linn.). 

 Syst. (ed. xii.) 1245. 



One shell from Launch Camp, three complete examples from Camp III. (2500 ft.), 

 one from unknown locality. 



5. Antinous anthropophagoeum, gen. et sp. n. (PI. XXXII. figs. 3, 4 «, 7, 8 a, * ; 

 PI. XXXIII. fig. 6 a~c.) 



One complete specimen, Camp XIII. (10,500 ft.). 



Antinous, gen. n. 



Foot-sole undivided, dorsal mucous pore lacking a covering tongue. A single 

 rudimentary shell-lobe ("?) is present ; the radula resembles that of Microcystina and 

 there is a simple jaw. The genitalia are near those of Rhysota, but the proximal 

 portion of the vas deferens is swollen out, while the seminal channel of the penis has 

 its margin much plicate at its distal extremity. The shell is bluntly carinate, perforate, 

 with a simple aperture and a non-reflexed columella. 



Antinous anthropophagorum, sp. n. 



Systematic Position. — It is impossible as yet to decide upon the exact systematic 

 position this genus occupies among the Zonitidse. Clearly referable to that family, in 

 spite of the absence of longitudinal subdivision of the foot-sole, it does not readily 

 fall into line with any of the forms of which the anatomy is known. 



The general form of the genitalia allies it with Rhysota (2), but the characters of the 

 mantle-lobes and radula distinguish it from that genus. On the other hand, the radula 

 has a good deal in common with that of Microcystina * [cf M. sapplw (6)] ; but 

 sundry characters, such as those of the mucous gland, male generative organs, and shell, 

 distinguish it from that group. 



A. External Appearance. 



The colour of the specimen (preserved in alcohol) is very dark bluish grey on the 

 dorsum and sides of the foot, while the sole is dirty yellow suffused with pale orange 

 (in life the whole sole was possibly orange-coloured). The mantle is dark grey, with 

 a broad dirty yellow border, the extremity of which is edged with a bluish-black rim. 



The sole is undivided. There is a broad peripodium (PI. XXXII. fig. 8 h) with 

 two closely approximated peripodial grooves. A dorsally placed caudal mucous pore 

 is found (PI. XXXII. fig. 8«), from which a covering tongue is lacking. The dorsum 

 of the foot is characteristic. Its sagittal axis is occupied by an irregular groove, from 

 which are given off bilaterally at regular intervals a number of posteriorly directed 



* Cf. also Bensonia luzonica (9). 



