of the Order Docoglossa. 287 



tomical investigations upon my part, which, so far as I am 

 aware are the only ones, including the whole order, which 

 have been made. I am indebted to Prof. Gill for suggestiuff 

 the very appropriate names by which I have designated the 

 suborders as restricted. 



Class GASTEROPODA. 



Order DOCOGLOSSA, DaU ex Trosch. 1870. 



Suborder ABEANCHIATA (GHl), Dall, 1870. 



Radula furnished with a rhachidian tooth and two uncini 



Animal destitute of eyes, branchi^, and lateral teeth on the 



area. 



Family Lepetidae (Gray), Dall, 1869. 



Shell patelliform ,• apex erect or anteriorly directed. Muzzle 

 ot the animal with an entire edge ; fm-nished with a tentacular 

 appendage below on each side. 



Formula of the radula, j^— ^. 



Genus Lepeta, Dall ex Gray, 1869. 

 A. Lepeta^ Dall. 

 Rhachidian tooth tricuspid, concave in front ,• central cusp 

 simple, much the largest; lateral cusps small, emarginate, 

 base very broad ; uncini with simple cusps. 



Tj^Q Lepeta cceca (Gray), Dall, Am. Jom-n. Conch. 1869, 

 v. p. 141. 



B. Cryptobranchia^ Dall ex Midd. 1869. 



Rhachidian tooth with three short cusps, equal and parallel 

 before and behind, not pointed ; base moderately broad, more 

 or less ornate behind ; uncini with simple cusps. 



Type Gryptohranchia concentrica (Midd.), Dall, Am. Joui'n 

 Conch. 1869, V. p. 143. 



c. Pilidium, Dall ex Forbes, 1869. 



Rhachidian tooth tricuspid, central cusp much the largest 

 convex in front ; lateral cusps simply pointed ; base narrow • 

 uncini with cusps obliquely twisted. ' 



Type Pilidium fulvum (Forbes), Dall, Am. Journ. Conch 

 1869, V. p. 146. 



Suborder PEOTEOBRANCHIATA, Dall, 1870. 

 Animal provided with three lateral teeth, with eyes, and 

 with external branchiae. Rhachidian tooth usually wanting. 

 Uncini present or absent. 



