2 TESTACELLID.E. 



Animal, as in other members of the family, with the anterior 

 portion of the body, or neck, much longer than the posterior 

 portion, or tail, which is very short. The colour is bright yellow, 

 often becoming scarlet on the eye-pedicels and upper portion of 

 the head. Upper tentacles or eye-pedicels elongate, lower tentacles 

 short. Genital orifice on the right side, near the respiratory 

 orifice and at a considerable distance from the tentacle. 



[The description of the internal anatomy is taken from Ferd. 

 Stoliczka's paper on the genus : — 



In the main points {vide fig. 2) " the organs are quite similarly 



arranged as in the Helicidse The mantle is above, at the 



pulmonary orifice, considerably produced, receding ventrally, but 

 remaining entire. On the inner side it has near the margin an 

 elongated, thickened appendage on each side of the pulmonary 

 opening. The pulmonary cavity itself is very long, but the lungs 

 narrow. The digestive system differs from all Helicidse which I 

 have examined by the peculiar development of the buccal parts. 

 The mouth is wide, and immediately behind it, where it makes 



an angle, lies the nervous ring Immediately behind the 



nervous ring the buccal parts are produced into a cylindrical 

 muscular tube, which extends in a slight curve up to the end of 

 the chief retractor muscle of the body, Avhere it is firmly attached 

 by a special thick muscle. A few separated threads connect the 

 mouth direct Avith the anterior end of the retractor. The ring- 

 muscles forming the outer layer of the tube are almost horny, or, 

 at least, very tough. The longitudinal muscles forming the 

 internal layer are much softer, but considerably thicker." 



This description recalls the buccal mass of Testacella and its 

 powerful muscles. It suggests Strej^taxis being carnivorous and 

 having a protrusive mouth, enabling it to enter and use the radula 

 within the whorls of other snails. Stoliczka pointed out the 

 similarity of the teeth of the radula to those of Testacella. There 

 are other points of similarity, such as the tube-like clusters of the 

 hermaphrodite gland and the form of the male organ (vide 

 Proceedings of the Malacological Society of London, vol. i. plate i. 

 figs. 14 & 16).] 



Genital organs simple, albuminous gland elongate ; herma- 

 plirodite gland small, composed of a cluster of tubes, the duct 

 long and much twisted. Spermatheca small and globular, with a 

 narrow neck [attached to uterus for nearly the whole length]. Vas 

 deferens very short. Penis short, muscular, the retractor muscle 

 long and thin and attached to the commencement of the penis 

 close to the junction of the vas deferens ; no flagellum or kale-sac. 

 Eggs large and well developed in the oviduct. 



Eadula long and narrow, composed of numerous rows of simple, 

 almost straight and pointed teeth, [40-60 in row,] each furnished 

 with a small swelling or projection about halfway between the 

 point and the base. The median tooth in each row scarcely 

 differs in form from the lateral teeth. The row is curved into an 

 arc on each side of the middle, with the concavity in front. 



