1873.] F. SioWczksi—Lajid-shelh of Fenant/ Islaml. 25 



dente, ad marginem umbilici obtuse angulato ; apertura semihinari, labio 

 tenui, labro expanse atque reflexo, ad insertionem umbilicalem panlulum 

 dilatato, ad basin indistinete subangulato, pallide violaceo tincto. Diam. 

 maj. 16, diam. min. 14"5, lat. apertura? cum perist. 8"8, ejusd. alt. 8*2 m. m. 



As regards the thin, almost horny, fulvous, thickly and finely setose 

 structure of the shell, this species is probably most closely allied to T. erinacea^ 

 Pfr., but it differs from it, as well as from two other very similar forms, 

 T. quieta, Reeve, and T. eustoma, Pfr., by its conspicuously more elevated 

 spire. Other species of similar type, like T hreviseta, Pfr., from Siam, 

 T. Helferi, Bens., from the Andamans, and four or five others described by 

 Pfeiffer and E. v. Martens have nearly all a more depressed form and mostly 

 sub-angular last whorl, although their spire is somewhat elevated. 



The animal is dark chocolate brown, with a very narrow pale dorsal and 

 caudal stripe, the body is laterally somewhat more blackish in front, and 

 tinged brownish behind ; the posterior end of the foot is the shorter one, as 

 in Trocliomorplia, although not to the same extent. 



The jaw is quadrant shaped, with about six strong ribs,* and one or two 

 less distinct ones on either side ; it is 1*3 m.m. broad. 



The radula is about 2*5 m.m. long., and 1. m.m. broad ; there are 95 

 transverse rows, and 91 teeth in each of them, decreasing in size the more 

 they approach the edges. The centre tooth is slightly smaller than the first 

 laterals. All have a large basal plate, which is on the centre tooth slightly 

 emarginate in the middle of the upper edge ; this emargination increases in 

 depth on the laterals, the inner branch remaining smaller, until on the last 

 ones the upper edge becomes represented by two obtuse branches. The hook 

 is on all teeth comparatively small, broad, with a moderately sharp point. 

 On about the tenth tooth a small denticle appears to shew on the outer edge 

 near the tip, becoming more distinct on the following teeth. After the 

 eighteenth lateral, the teeth become somewhat more rapidly shorter, but 

 increase in width until the last are wider than long, or high, and on 

 these the basal plate has almost entirely become obsolete. 



The genital organs are more than an inch long. The female portion 

 has a long seminal receptacle, strongly thickened and muscular for some 

 distance from its origin, then passing into a long thin tube and ter- 

 minating with a moderately enlarged bubble, attached by very thin 

 muscular fibres to the albuminous gland which is situated at the end of 

 the uterus. The vas deferens takes its origin near the upper end of 

 the uterus ; it is attached by numerous thin threads at the hermaphrodite 

 opening, and after a short distance enlarges into a muscular tube. At the 

 beginning of this enlargement is a short pointed flagellum (/), and at the 



* Evidently very mucli like that of Campylcea. 



