MUSEUM OF COMPARATIVE ZOOLOGY. 285 
This little species was overlooked in my preliminary examination and taken 
for the young of the preceding. A more careful study shows they are abso- 
lutely distinct. 
Famity VERTICORDIIDA Srcuenza. 
Genus VERTICORDIA Woop. 
Verticordia (Wood Ms. 1844) Sowerby, Min. Conch., pl. 639, Aug. 1844. 
Verticordia (Wood Ms.?) Gray, Syn. Brit. Mus., 1840 (sine descr.). 
Hippagus Philippi, Sowerby, not of Lea. 
Iphigenia O. G. Costa, 1850, not of Schumacher, 1817. 
Verticordia Seguenza, Journ. de Conchyl, 1860, p. 286; Fischer, |. c., p. 295; 
Seguenza, Rendic. R. Accad. delle Scienze, 1876. Dall, Bull. M. C. Z., IX. 
p. 105, 1881. 
Since my examination made in 1881 of the specimens of this group, I have 
been able to examine alcoholic specimens of V. acuticostata and additional 
specimens of other species, beside those contained in the Jeffreys and U. S. 
Fish Commission collections. I have therefore reviewed the whole subject, 
and have the pleasure of being able to add several facts of interest, and espe- 
cially to determine positively the relations of the animal and the character of 
the soft parts in the species referred to, and therefore probably for the whole 
group. I have found also that the shells which have been referred to this 
group differ among themselves in regard to characters of hinge and dorsal mar- 
gin, so as to require separation into different subgenera or sections. 
VERTICORDIA (s. s.). Shell small, more or less convex, with a deeply im- 
pressed lunule and a large, arched, bridge-like ossicle attached below the beaks 
to an internal cartilage in each valve ; this ossicle is expanded outward at its 
posterior end, and, in the most typical species, is much broader than long ; 
the right valve has a strong conical tooth behind the internal convexity due to 
the impressed lunule, and no lateral tooth ; the left valve has the lunular edge 
produced to fit in front of the cardinal tooth of the right valve, and has the 
upper surface of the posterior hinge-margin bevelled away so that that edge 
may fit under the opposing edge of the right valve ; the cardinal tooth in 
young specimens is grooved axially, but when adult is conical; the line of the 
external ligament is continued under the spiral of the beaks. Soft parts (in 
V. acuticostata Phil.) having the mantle-edge thick and fleshy, corresponding 
in form to the sulcations of the valves, but not fringed with papille; united 
on the ventral surface, with a simple very short slit opposite the foot; with a 
papillose siphonal opening posteriorly (the anal siphon probably present as in 
_ Lyonsiella, but, on account of contraction from the spirits in which it had been 
preserved, not clearly made out) with about four ranks of papille, the inner- 
most ones largest, but in the specimen much contracted. Mouth axially 
