COLLINGE : A NEW SPECIES OF CRYPTOSOMA. 3 



Shell (PI. i, fig. i) apex depressed, thin, strise definite, brownish 

 or horn colour. 



Hab. Calcutta (Coll. of W. E. C). 



I have given in figure 5 a part of the generative organs of C. 

 prcvstans^ Gould, built up from the three figures given by Godwin- 

 Austen (/. c.) for comparison with those in this species (PI. i, fig. 4). 



In C. aiiste/ii the vagina is a long straight tube, from the top of 

 which the elongated sessile receptaculum seminis opens. The free- 

 oviduct is a wide tube gradually expanding as with "the vas deferens 

 it gives place to the oviduct proper and prostate. The penis is a 

 short, broad tube, constricted on its inner surface (PI. i, fig. 4, /). 

 In C. prffsians, Gould, Godwin-Austen describes the penis as being 

 '' much convoluted and closely folded together," which feature is 

 shown in fig. 9 (/. r., pi. iv). In C. misieni the penis lies ventral to, 

 and at the outer side of, the vagina and free-oviduct. At the distal 

 extremity and on its dorsal side, there is a small kale-sac given off, 

 unfortunately this was damaged in dissection. I believe it was a 

 somewhat ovoid-shaped body and a little larger than the receptaculum 

 seminis, but as I am not quite certain, I have left it incomplete in 

 figure 4. From the inner and dorsal side of the penis, at a point 

 almost exactly opposite to the origin of the kale-sac, the vas deferens 

 arises, the retractor muscle of the penis being inserted above and 

 between the two (PI. i, fig. 4, r. m.). The dart-sac is a wide muscular 

 tube, narrowing slightly as it approaches the U-shaped bend towards 

 the distal end (PI. i, fig. 4, d. s.). The distal extremity is rather 

 narrower and pointed. There was no dart present. 



A comparison of the terminal ducts of the generative organs of 

 C. auslcni, with those of C. pmsia/is, Gould, shows many striking 

 differences. The peculiar-shaped dart-sac in this latter species with 

 its bulbous proximal end, is very distinct from that organ in C. austeni, 

 while in the form of the penis and receptaculum seminis, the differences 

 are still more striking. 



Externally there are also a few interesting points of difference 

 from C. prtestans^ in the shape and size of the mantle and shell-lobes. 

 The left shell-lobe and left dorsal lobe of C. austeni are considerably 

 smaller than in the former species, while the right shell-lobe and the 

 right dorsal lobe are much larger {cp. Godwin-Austen, /. c, pi. iv, 

 figs. 2 — 5). In life the right shell-lobe of C. austejii must extend a 

 considerable distance over the surface of the shell, much more so 

 than is shown in Stoliczka's beautiful figure of C. prccstaiis, given by 

 Godwin-Austen (/. c. \)\. iv, fig. i). Finally the shell of C. austeni is 

 smaller, thinner, and much more fragile than that of C. pnrstans, 

 Gould. 



