THE NAUTILUS. 



Vol. XXXV APRIL, 1922. No. 4 



THE HELICOID GENUS LEPTAXIS LOWE 



BY T. D. A. COCKERELL 



Professor Pilsbry, iu Ms guide to the Helices, treated 

 taxis as a valid genus, including the groups Leptaxis proper, 

 Pseudocampylcca Pfeiffer, and Lampadia Albers. Cryptaxis 

 Lowe and Katostoma Lowe were merged iu true Leptaxis. 

 Unfortunately the anatomy of only one species, undata, was 

 known. I am greatly indebted to Mr. C. B. Cossart for living 

 specimens of L. erubescens Lowe and L. vulccmia Lowe, 

 which he collected last month on Deserta Grande. The geni- 

 talia of erubescens prove to be of the same general type as 

 those of L. undata, but with some striking differences, the 

 most noticeable character being the regularly globose sperma- 

 thecal bulb, in contrast with the boot-shaped structure of L. 

 undata,. That this feature of the spermatheca is not purely 

 a specific one is shown by L. vulcania (pi. 3, fig. 14), which 

 has the boot-shaped form of undata. Other features of eru- 

 bescens (pi. 3, fig. 13) are: albumen-gland very large; penis- 

 sac elongate, abruptly contracted at the beginning of the 

 flagellum, which is about 5 mm. long; spermatheca with duct 

 8 mm. long; dark-sac as usual in the genus; filiform glands 

 about 11, simple, three attached longitudinally. In L. vul- 

 cania the flagellum is much longer, about 12 mm., but the 

 snail is much larger. I examined the radulse of erubescens 

 and undata in the Gwatkin. collection. They differ appre- 



