PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 373 



ture none, except indistinct lines of growth ; surface smooth and shin- 

 ing throughout. 



Length of the animal in life about 15""" to 20"""' ; length of shell, 12.5""; 

 breadth, lO"". 



Stations 870 to 872, south of Martha's Vineyard, in 86 to 155 fathoms, 

 fine sand (16 specimens, living). 



The shell of this species, in form, closely resembles that of the Eu- 

 ropean L. perspicua (not of Gould), but the dilferences in the mantle and 

 dentition will clearly separate it. Specimens of both sexes occurred, and 

 they had the same form and color externally. 



The ^^Lamellariaperspicua^^ of Gould was based, in part at least, upon 

 Marsenina glabra. A species of Lamellaria occurs at Eastport, Me., 

 which may be distinct from the preceding. 



Marsenina prodita (Loven) Bergli. 



G. O. Sars, Moll. Reg. Arct. Norv., p. 151, pi. 12, figs. 5 a-c ; pi. v, figs. 7 a,h 

 (dentition). — Verrill, Trans. Conn. Acad., v, pi. 42, figs. 2, 2 a. 



This species was taken, living, at Eastport, Me., by Prof. S. I. Smith 

 and myself, in 1864 and 1868. It is easily recognized by its compara- 

 tively prominent, acute spire, turned to one side, by its obliquely elon- 

 gated aperture, and by the margin of the outer lip being slightly inflexed 

 near the suture. It has not been previously recorded from the American 

 coast, south of Greenland. 



Marsenina glabra Verrill. 



Oxinoe gldln-a Couthouy, Boston Jonrn. Nat. Hist., ii, p. 90, pi. 3, fig. 16, 1838. 

 Lamellaria perspicua (pars) Gould, Binney's ed., p. 337, fig. 607 (?). 

 Marsenina micromphala Bergb. — G. O. Sars, op. cit., p. 151, pi. 21, figs. 10 a-d. — 

 Verrill, Trans. Conn. Acad., v, pi. 42, figs. 1, la. 



This species is not uncommon at Eastport, Me., where I collected it in 

 1859, 1861, 1863, 1864, 1868, 1870, and 1872. It was dredged last year 

 by our party, on the " Speedwell", off Cape Cod, in 34 fathoms. It has a 

 much smaller and less prominent spire than the i^recediug, and a more 

 regularly oblong-oval ai^erture. The shell is smooth, white, thin, and 

 delicate in both species, but more translucent in the present one. 



There can be no doubt, from the description and figure, that the Oxinoe 

 glabra of Couthouy was a Marsenina indistinguishable from this species, 

 which is the commonest of the group on our coast. The 21. microm- 

 phala, well described and figured by Sars, appears to agree perfectly 

 with our form, both in the animal and shell. 



Gould appears to have confounded two or more species under his L. 

 perspicua. His figure (158) in the first edition does not represent this 

 species ; the figure 607 of Binney's edition is different, and may be this 

 shell. As a genuine Lamellaria, having its shell entirely inclosed in the 

 mantle, also occurs on our coast, not rarely at Eastport, Me., it is not 

 improbable that Gould may have had its shell among those examined 

 by him. Its identity with L. perspicua of Europe is very doubtful, 

 however. 



