THE NAUTIU^S. 

 AN AMEKICAN ANADENUS. 



BY HENRY HEMPHILL. 



Recently, on the Cuyamaea Mountains in San Diego County, 

 California, I was fortunate in finding specimens of what proved to 

 be a genus new to America. Submitting them to Mr. Binuey and Mr. 

 Cockerell, they agreed with me in referring these species to Anad- 

 enus, formerly known of only from the Himalaya Mis. 



The genus is characterized thus by Binney in his Genera of Slugs 

 — " Animal limaciform, subcylindrical, tapering behind; tentacles 

 simple ; mantle anterior, concealing an internal shell-plate ; no 

 longitudinal furrows above the margin of the foot, and no caudal 

 mucus pore ; a distinct locomotive disk ; external respiratory and 

 anal orifices on the right posterior margin of the mantle ; orifice of 

 combined genital system behind and below the right eye peduncle. 



Internal shell-plate small, oval, flat, with posterior nucleus and 

 concentric stride. 



Jaw with numerous ribs. 



Lingual membrane with tricuspid centrals, bicuspid laterals and 

 quadrate marginals." 



The genus differs from Prophysaon by its posterior respiratory 

 orifice, the position of the genital orifice and by its locomotive disk. 

 It will, however, be remembered that Fischer considers Prophysaon 

 a subgenus of Anadenus. The distinction between the two is slight, 

 especially as regards the respiratory orifice. The living slugs found 

 by me had it slightly posterior. In alcoholic specimens of this and 

 many of the Prophysaons it is difficult to detect its true position, so 

 nearly subcentral is it. 



Anadenus Cockerelli, n. sp. 



Length contracted in alcohol 13? mill. Mantle 4? long, 2| wide. 

 End of mantle to end of body 8. Foot 2 wide. Foot with a loco- 

 motive disk, being distinctly differentiated into median and lateral 

 tracts. Respiratory orifice slightly posterior, on right edge of man- 

 tle. Genital orifice below right tentacle. No caudal mucus pore. 

 Locomotive disk narrow, only half the width of the lateral areas. 

 Sides of foot wrinkled, but not difl^erentiated from lateral areas, nor 

 specially marked, the wrinkles being a continuation of the transverse 

 grooves of the lateral areas. Mantle tuberculate rugose, oval in out- 

 line, bluntlv rounded at either end, not grooved as in Anvdia. Man- 



