Athomcophorus.] GASTROPODA. 807 



narrow ridge, the continuance of the front of the head. The whole 

 of the notum and anterior part of head are covered by numerous small 

 and sharply raised papillae, the interspaces minutely granular. Median 

 groove distinct, slightly deviated to the left at the mantle-aiea ; the 

 oblique lateral grooves are rather close together, especially near the 

 mantle ; their number is about 20 on each side, half of which are 

 post-pallial. PJead-shield triangular, reaching to the middle between 

 head and mantle-area ; there is a shallow median groove. Mantle- 

 area transversely triangular, perfectly closed by grooves, papillate, 

 the respiratory orifice in the middle near the median groove, the anus 

 in the outer angle. Plate states that the anus is close to and in front 

 of the outer mantle-groove, but in all the specimens I have examined 

 it is inside the mantle-groove. Renal opening in the inner anterior 

 angle of the mantle-area, with a small oval flap. Gemini orifice outside 

 the right tentacle in the frontal groove. Hyponotum prominent, 

 moderately broad, the perinotum marked by a thread-like cord. Sole 

 not very broad, separated from the head by a deep groove. Through 

 contraction in alcohol, the hyponotum and. sole are transversely 

 grooved, and the latter aulacopod. Shell rudimentary, consisting, as 

 usual in the genus, of a number of irregularly shaped calcareous grains 

 of various size. 



Measurements : Length over back from head to tip of tail, 29 mm. 

 Width of back to perinotum, 11 -5 mm. Sole Length, 24mm.; 

 breadth, 4-5 mm. Breadth of hyponotum, 2 mm. Distance of anus 

 from right tentacle, 9 mm. Distance of anus from pulmonary orifice, 

 2-5 mm. Distance of pulmonary orifice from head, 12-5 mm. 



Jaw small, elasmognathic, the median projection broadly triangular, 

 rounded. 



Radula with numerous teeth. Sirnroth states that the radula is 

 similar to that of A. Martensi, but the lateral teeth have 5 to 7 den- 

 ticles instead of only 4 to 6. The radula I examined had no central 

 tooth ; the lateral teeth meeting in the median line were alternately 

 one in front of the opposite tooth, thus forming a zigzag line. The 

 inner lateral teeth with 9 denticles, the first large, the second minute, 

 the third about half the length of first, and the outer ones minute. 



Reproductive Organs. The hermaphrodite gland imbedded close 

 to the salivary glands, so that the hermaphrodite duct is directed 

 backwards. Spermoviduct present ; oviduct cylindrical, not much 

 enlarged above, but widening below, and carrying inside a hard longi- 

 tudinal fold ; prostate well developed ; no accessory glands. Kecep- 

 taculum seminis oval, proximal, with a short neck. The vas deferens 

 is long, and enters the male organ at its distal end, where the retractor 

 muscle is also affixed. Sheath of male organ long, spindle-shaped ; 

 the everted verge is 3 mm. long, cylindrical, with 6 longitudinal ridges 

 of crowded high and fine papillae, the edge of the ridges having the 

 appearance of a saw ; the grooves between the ridges transversely 

 striated. 



