GODWIN-AUSTEN : ANATOMY OF ARIOPIIANTA AMPULLA, BENS. 189 



It is short, and at its anterior end is attached to a long, straight 

 B caecum {c.r.p.), given off at the main bend of the male organ. Near 



- the base this is bent on itself into an S-shape connected by muscles. 

 I There is only an indication of a flagellum or kale-sac ; the vas- 



deferens joins an oval enlargement, in which a short spermatophore is 



- in process of formation, but as there are only two specimens I have 

 r not attempted to take it out. The amatorial organ is very stout and 

 j rounded at the posterior end, giving off a long retractor muscle ; 

 i it has its attachment on the side of the body-cavity, and several 

 , strong, short muscles near the anterior end attach it to the floor of 

 i the foot just behind the buccal mass. The spermatheca is very short, 

 i of oval form, on a short stem. Since there is some importance in the 

 j relative position of the different parts of the genitalia, etc., when 



packed together in the body-cavity, I give drawings taken from above, 

 ; and from the right and left and front sides. The penis is central and 

 dorsal ; the spermatheca, free oviduct, and part of the vas deferens 

 appear on the right side ; the amatorial organ is scarcely seen, since 

 it rests on the side of the foot, and is hidden by the buccal mass 

 and the capacious stomach. 



The principal retractor muscles are well displayed. The main 

 retractor of the right eye tentacle has its attachment on the right- 

 hand side of the body-cavity, under the edge of the mantle-zone and 

 right dorsal lobe. Another, broad one, shows beneath the last, on 

 the right-hand side of body. This gives off two smaller muscles, 

 attached near the margin of the mantle-zone. 



The jaw is peculiarly straight, with only a very slight convexity on 

 the cutting edge. It is solid and elongate, slightly more than four 

 1 times longer than wide. The radula is broad, with about 100 rows of 

 , teeth, arranged thus : 



145 : 17 : 1 : 17 : 145. 



There is no very well marked line between the thirty- five central 

 teeth and the laterals that follow. The rhachidian tooth and the 

 admedians are long, broadly pointed, straight- sided ; the succeeding 

 marginals are curved, aculeate, and rounded at the point; at about 



' the 130th tooth the marginals become bicuspid, the inner cusp being 

 the longer. 



In its main characters, such as the mantle-lobes and the generative 

 organs, this species agrees with Nilgiria and Ariophanta, and in points 

 of detail is as near to Nilgiria Chenui as any other species. In the 

 radula and jaw there is divergence, but the aculeate laterals have 



' their counterpart in species of the Ariophantinae, such as N. bistrialis, 

 N. Ceylania, N. Chenui, and N ganoma, in which also the median band 

 of teeth is broad ; and Ariophanta cgsis, A. immerita, A. interrupta, 

 A. bajadera, and A. intumescens. 



The peculiar characters which it does not share with these are — 

 (1) the jaw, (2) the form of the central or median teeth, (3) the very 

 smooth sole of the foot, (4) the pallia! margin, (5) the shell. It 

 appears to me these are sufficient data on which to found another 

 subgenus of the Ariophantinae. The shell alone, in the eye of 



