408 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



ward into a tentacle-like filameut on each side; sliell patelliform, with 

 a subspiral nucleus, which is generallj-^ lost in early life, the permanent 

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



Subfamily LEPETELLIN^ n. 



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

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

 unciui. Tyincal genus Lepetella Verrill. 



Genus Lepetella Verrill. 



Lepetella Yerrill, Am. Jouru. Sci. xx, p. 396, Nov. 1880. 



Type Lepetella tubicola Verrill 1. c, also Proc. U. S. l^nt. Mus. iii, p. 

 375, Jan. 1881. 



Habitat. — In two to four hundred fathoms of the SE. coast of I^ew 

 England (stations 869 and 894, U. S. Fish 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 o^ belonging 



to the order Tccnioglossa, which has a formula oto, while the formula of 



Lepetella is -. /■>..)r i, the essential difference being that all Tcenioglossa 



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

 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 animal.* So far as the external features could be determined 

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

 Cryptohranchia. The dentition is remarkable, both in relative number 

 of teeth and in presenting the only instance of a well-developed, distinct, 

 scale like (chitonoid) nncinus 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 limpets in 

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

 peculiar 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 have, however, no doubt of their existence. A letter from Dr. J. Gwyu Jeffreys 

 states that a small limpet like Lepeta, but with eyes, has been dredged off the coast of 

 Norway by Prof. G. 0. Sars, which may probably jirove to be Lepetella. 



