222 Records of the Indian Museum. [Vol. VIII, 



does not seem to be connected to any other muscle strands passing 

 to other portions of the body- wall. It seems to be the remains of 

 the well-developed colmnellar muscle of typical pulmonates. 



Prisma aborense, n. sp. 



A single specimen of the present species was obtained under 

 stones at Rotung, 1300 ft. 



The animal seems to belong to a new species. The presence 

 of precephalic flaps is a remarkable point to note. 



Notum finely granulated, with small tubercles in addition. 

 Notum of sepia colour with black dots and lines, the latter forming 

 an open meshwork not symmetrical on both sides. Foot sole light 

 lamp-black, with the rims and circumpedal groove (including the 

 inner surface of the free mantle margin) yellowish white. Body 

 prismatic in transverse section with a faint rounded keel in the 

 middorsal line. Mantle forming a hood over the head ; mantle- 

 margin thick and directed inwards. A thick precephalic flap 

 beneath each lower tentacle and fused with it. Tentacles and flaps 

 slaty-black. Length of notum 27 cm., breadth "15, height '7, 

 breadth of foot sole '3, 9 aperture '35 from & aperture. 



External Characters. 



The animal is elongated, limaciform and is prismatic in trans- 

 verse section. The height of the body is greatest in the middle 

 third of its length. The body tapers slightly to a rounded end 

 anteriorly, and gradually to a bluntl^^-pointed end behind, the 

 margin of the mantle (perinotum) being inflexed at the latter end. 



The mantle is rounded with a keel in the middorsal line. The 

 keel is prominent and ridge-like in the anterior-third of the body, 

 but is broad and rounded in the posterior two-thirds. The fore- 

 most part of the mantle is bent at a right angle to the part behind 

 and forms the hood covering the head. The hindermost part of 

 the mantle is bent downwards and forwards just behind the pos- 

 terior extremity of the foot, the outer surface being thus directed 

 downwards and backwards. The anterior border of the mantle 

 presents a wide rounded notch in the middle line. The mantle- 

 border (perinotum) is thick and slightly inflexed; it forms a convex 

 surface about '08 cm. wide, which narrows down to disappear at 

 the posterior end. The surface of the mantle is granulated. 



The head is separated from the body by a distinct transverse 

 groove. The ommatophores are short, stout and cylindrical, they 

 are transversely wrinkled, and seem to be non-invaginable. The 

 precephalic flaps are placed on the lateral aspects of the head, and 

 form the lateral boundary of a trapezoid-space leading into the 

 mouth. The two flaps are united to each other by a thin narrow 

 flap of integument extending across the middle line beneath the 

 ommatophores, and forming the dorsal wall of the trapezoid spaces 

 mentioned above. The outer (dorsal) surface of each precephalic 



