BATNADVIPIA. 



75 



An amatorial organ (dart- sac) present, large and cylindrical; 

 no calcareous dart found, but a short blunt muscular papilla. 

 Spermatheca sessile. The vas deferens passes into a kale-sac, 

 which is joined to the penis -sheath, some distance from the 



[Fig. 38. Ratnadvipia irradians. 



A. Animal from right side, showing the shell- and dorsal lobes ; also part of, 



from the left side. The shell-lobes are curled up in the spirit-specimen ; 

 the dotted line on visceral sac indicates their extension in life. X 1"9. 



B. Part of genitalia showing the typical male organ of Ariophanta. x3'4. 



C. Jaw and teeth of the radula. X 268.] 



retractor muscle, by an epiphallus ; caecum of penis straight, as in 

 Arioplianta. 



This genus differs frdin Lidrella chiefly in the possession of 

 shell-lobes to the mantle, and in the absence of lateral cusps to 

 the teeth of the median band in the radula. 



