138 VITRINID^B. 



species have been described ; they are inhabitants of warm 

 countries, replacing the Vitrinas of the more temperate regions, 

 and are found in Southern and Eastern Asia, Malaysia, Philip- 

 pines, Australia, Abyssinia, etc. 



Several sections have been proposed, founded mainly on 

 characters of the animal. As in many of the species the animal 

 is unknown, it is diflicult to arrange the species in accordance 

 with these sections. 



Section CRYPTOSOMA, Theobald. Shell like Helicarion, but 

 more robust. Animal capable of retraction within its shell ; tail 

 truncate ; mucous pore large, without overhanging lobe ; right 

 shell-lobe of mantle moderately large, extending over the region 

 of the body-whorl, and quite around to the posterior margin, 

 where it unites with the left shell-lobe, which is very long and 

 well developed, and spreads over the edge of the peristome from 

 near the respiratory orifice. The right dorsal lobe is triangular 

 in shape, and the left dorsal lobe is long and rather narrower 

 than the shell-lobe adjacent. Jaw strong, straight in front, 

 longitudinally striate. 1 sp. Burmah. 



Section AUSTENIA, Nevill, 1878. Shell Yitrinoid, depressed ; 

 with fewer, more rapidly enlarging whorls than in typical Heli- 

 carion. The animal is somewhat slug-like in appearance, but 

 with a well-formed shell. The shell-lobes ample. The right 

 dorsal lobe extends from the respiratory orifice to the posterior 

 right margin. The left dorsal lobe is large in front, and extends 

 from the same part to the left margin. The shell-lobes are con- 

 nected all around the periphery of the mantle-zone, but are 

 reduced in size and present two distinct right and left contrac- 

 tile lobes ; the right extends to and covers the apex of the shell, 

 while the left extends over the edge of the body-whorl for a 

 short distance, leaving the posterior and the greater portion of 

 the upper surface of the shell uncovered. The posterior margin 

 of the shell is not sunk in a depression of the hinder part of the 

 foot, but the upper surface of the foot extends in an unbroken 

 ridge to the mantle-zone. Extremity of the foot truncate, with 

 a large linear mucous gland, with or without an overhanging 

 lobe ; the pedal line very distinct. The sole of the foot with a 

 central separate area. Southern Asia. 



