HYALIMAX. 499 



minute papillae ; there is no division into right and left shell- 

 lobes ; the dorsal lobes are very much reduced in size, the right 

 dorsal lobe particularly so, being very narrow and only extending 

 to the posterior margin ; the left dorsal lobe is also very narrow, 

 and only just separated from the mantle, terminating on the left 

 anterior side. The respiratory orifice is just behind the centre 

 of the right side of the mantle, a short distance above its lower 

 edge. The anal orifice is some distance (3 mm.) behind it, and 

 concealed by the mantle, its position being quite on the right 

 posterior margin. 



" The shell is ovate, thin, flat, transparent, milky white, with 

 close concentric ridges of growth, very thin and delicate on the 

 margin ; the apex rather more solid and quadrate at that end, the 

 nucleus being on the right margin. 



" Size : major diarn. 5 mm., minor diam. 3*3 mm. 



" Length of spirit-specimen 16, mantle 11, breadth 5*5 mm." 



Hah. Andaman Islands : Port Blair (Harold Godwin,- Austen). 



" Odontophora, cf'c. The buccal mass is large ; the strong 

 retractor muscle has its attachment, together with that of the 

 eye-tentacles, in the usual position at the posterior side of the 

 mantle-margin ; but the posterior portion of the buccal mass is 

 very different to what we find in other species ; it is more 

 truncate ; and that part where the lingual ribbon takes its origin, 

 and which in all species I have hitherto examined presents a 

 shortish blunt knob-like process, in this species is represented by 

 two coils, which are really the posterior edges of the lingual 

 ribbon, turned up on each side and coiled on itself inwards. The 

 lingual ribbon is broader than it is long; and 92 rows were 

 counted, each containing at least 530 teeth : 



265 . 1 . 265 



" The central tooth is 4-cuspid and much hooked. The laterals 

 are all alike, very gradually becoming smaller on the outside ; 

 they bend over in a claw-like form, and are edged with four cusps, 

 of which the two outermost are slightly longer than the two 

 inner ; a very minute cusp can just be discerned in some of the 

 largest laterals near the centre, at the exterior base of, and next 

 the first long inner cusp. 



"The jaw is very peculiar. It is a very dark umber colour ; 

 the cutting or frontal edge forms an oblique angle ; and the 

 muscular attachment is very strong and extends back at right 

 angles, equal in length to the width of the jaw, which is T-shaped 

 as in Succinea, &c. 



"The- heart is situated on the left anterior margin of the 

 mantle. The position of the anus is very far back on the right 

 posterior side, quite removed from the neighbourhood of the 

 respiratory orifice, its usual position in most genera ; and this is 

 perhaps the most interesting point in the anatomy of this species. 

 The intestine terminates in a large expanded sac just within the 

 aperture. 



