408 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



ward iuto a tentacle-like filament on each side; sliell patelliforra, with 

 a sabspiral nucleus, which is generally lost in early life, the permanent 

 tip being- erect or anteriorly directed. Typical genus Lepeta Gray. 



Subfamily LEPETELLIN^ u. 



Shell and soft parts as in Lepetidcc, except that it has distinct eyes 

 and is provided with true lateral teeth and also with scale-shaped 

 uncini. Typical genus Lepetella Verrill. 



Genus Lepetella Verrill. 



Lepetella Verrill, Am. Jouru. Sci. xx, p. 393, Nov. 1880. 



Type Lepetella tuMcola Verrill 1. c, also Proc. U. S. Nat. Mus. iii, p. 

 375, Jan. 1881. 



Habitat. — hrtwo to four hundred fathoms of the SE. coast of New 

 England (stations 8G9 and 894, \J. S. Fi^h Commission, 1880) in old 

 tubes of Hyalinwcia artifex V. (Coast of Norway in deep water, Sars?) 



Professor Verrill has well described this little shell in the articles 

 referred to, as well as its dentition, which he calls Tsenioglossate. It is 

 indeed so in one sense, though not in the technical sense of belonging 



to the order Twnioglossa, which has a formula 07^, while the formula of 



Lepetella is 1 7v>.^vn ? the essential dilierence being that all Twnioglossa 



have on each side of the rhachidian tooth three laterals and no uncini, 

 while Lepetella has two laterals and an uncinus. 



The specimens examined by me were dry or from deterioration of the 

 alcohol had become quite soft, and for this reason, perhaps, I could not 

 detect the eyes seen by Professor Verrill so distinctly in the fresh and 

 living anim;il.* So far as the external features could be determined 

 there was no difference between them and those exhibited by Lepeta or 

 Cryptohrancliia. The dentition is reniarkable, both in relative number 

 of teeth and in i)resenting the only instance of a well-developed, distinct, 

 scale like (chitouoid) uncinus yet known in the order. In fact, the radula 

 has throughout distinctl.y Chiton-like features, and bears additional tes- 

 timony, if such were needed, to the acuteness of Troschel in combining 

 (dental characters only being considered) both chitons and limi)ets in 

 one dental order. The external form is, of course, partly due to its 

 l)eculiar habitat; other specimens will, no doubt, eventually be found 

 clinging to some flat surface and of normal shape. It seems to be a 

 northern form, and does not occur in the Blake collections. 



* I bave, however, no doubt of tbeir existence. A letter from Dr. J. Gwyn Jeffreys 

 states tbat a small limpet like Lepeta, but with eyes, has been dredged oti' the coast of 

 Norway by Prof. Qt. 9. Sars, which may probably prove to be Lepetella. 



