592 Records of the Indian Museum. [Voi,. VIII, 



lobe above the mucous gland having a vertical narrow slit. The 

 peripodial margin is well marked with the usual two parallel 

 grooves above it, from which 5 lateral distant grooves run up- 

 wards to the dorsal ridge of the foot and meet in a central main 

 groove. The extremity of the foot is bluntly keeled but only for 

 a short distance, it then flattens out very broadly from the central 

 groove above mentioned, the posterior part of the shell resting 

 upon it. This wing-like expansion is bordered on both sides by 

 four, we'll developed, contiguous, fleshy, pale coloured protuberan- 

 ces (plate liii, figs. 2 and 4), a very conspicuous and novel charac- 

 ter in this subfamily and one intimately connected with the seg- 

 mental divisions of the foot, which usually meet on the keel for its 

 whole length. 



The right shell lobe (plate liii, fig. 3) is 'fairly large, broad at 

 its base and narrowing to a fine point and lays up on the under 

 side of the body whorl. The left shell lobe (pi. liii, fig. 2) is narrow 

 and long; the right dorsal lobe fairly large, the left in two distinct 

 parts and the anterior the shortest. 



Generative organs. A large amatorial organ is present, 

 thickened considerably at the distal end, the dart is muscular. 

 The penis is a simple tube terminating in an oval mass which is 

 indistinctly spiral and on the side of which the retractor muscle is 

 attached. The flagellum is short and somewhat thick. The sper- 

 matheca is also short and elongatelv oval in form. The radula is 

 quite like that of Macrochlamys, with a formula 52. 14. 3. 1.3. 14. 52 

 or 69.1.69. 



The central tooth and admedians elongate and sharp-pointed, 

 the marginals all bicuspid. 



The shell of this species is of striking and unusual shape, but 

 the character possessing the greatest interest is the wonderful 

 development of the foot. Looking for similar evolution in this 

 part of the animal in terrestrial molluscs, we find in true Helicarion 

 helenae from Sydney introduced there from Queensland something 

 similar. The dorsal side of the foot is flattened out, with a central 

 groove running down it (vide Moll India, vol. I, pi. xli, fig. 4). 



In Pseudaustenia ater , G.-A., of Southern India {Moll. Ind., 

 vol. I, pi. Ivii, figs. I, 16), the hinder part of the shell rests 

 between fleshy wings, with, in this case, straight and sharp, not a 

 serrate edge, a bifurcation of the keel. This particular develop- 

 ment of the hinder part of the foot may be termed " the segmental 

 lateral processes," in contradistinction to ''segmental central pro- 

 cesses," as seen in the foot of Helicarion idae of Drs. Paul and 

 Fritz Sarasin in their fine work; " Die Land Mollusken Von Cele- 

 bes," p. 121, plate xvii, fig. 151; in this case the spiked edge is 

 produced by the elongation of epidermal granules. 



. The genus Eurypus of Semper is distinguished by its peculiar 

 foot (Reisen Archi. d. Philippinen , pi. i, figs. 16 and 17), shown res- 

 pectively in E. cascus of Viti, and E. similis of Fiji. Unfortunate- 

 ly the figures are so small, it is difficult to make out the exact 

 form. Interesting modification of foot structure in the mollusca 



