1074 MALAYSIAN LAND AND FRESHWATER MOLLUSCA, 



front above the mouth, which is sub-circular and angular 

 anteriorly in young specimens, which also present a little 

 canaliculate prolongation, which is obliterated little by little 

 as the animal is developed, leaving when completely closed only 

 the appearance of a triangular area traversed longitudinally by a 

 linear scar, and leaving in that state a rounded double peristome. 

 Internal lip relatively less thick, deeper coloured, and more 

 shining ; external reflected, but not always perfectly united with 

 the inner. Operculum testaceous, somewhat thick, with a central' 

 nucleus, and composed of two ]>lates ; external face multispirftl, 

 slightly concave in the middle ; internal face few whorls, also 

 slightly concave in the middle ; margin with a feeble keel. 



The foot is not divided as in the Cyelostomidse, where theie 

 are two longitudinal parts independent of each other for crawling 

 The animal is long, with a very thin mantle, whose anterior 

 border is simple and not papillose ; head and muzzle short, thick, 

 the latter grooved transversely on its upper face ; buccal orifice, 

 when open, oval, and showing the extremity of the radula, but 

 when the mouth is closed it is a simple slit ; tentacles short, 

 thick, transversely striate, slightly constricted at the base, of a 

 uniform reddish color ; eyes at the external base well pigmented 

 and placed on short, obtuse, and shghtly convex peduncles ; foot 

 thick, fleshy, wide, short, oval, obtuse, truncate in front, round 

 behind. There is a large pedal sinus in front, but no trace of 

 that longitudinal division which is common in the family of 

 Cyclostomidse, but the foot is rather that of the family of 

 Cyclophoridfe. The upper part of the foot carries the operculum, 

 the adherence of which is circular, with an umbilicated non- 

 central projection, which corresponds to the nucleus of the 

 internal face, so that half the organ is free, like the genus 

 Cyclophorus. The sexes are distinct, the females being a little 

 larger in size. The mouth has two mandibular plates, brown, 

 chitinous, and solid, visible to the naked eye, but when magnified 

 displaying a facetted structure roughly hexagonal or rounded. 

 This may possibly be some aiTangement connected with the eyes 

 of the animal, or a facetted eye-structure like that which exists 



