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. 



Family VERTICORDIID^ Seguenza. 



Genus VERTICORDIA Wood. 



Verticordia (Wood Ms. 1844) Sowerby, Min. Conch., pi. 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 Conehyl , 1860, p. 286; Fischer, 1. c, p. 295; 



Seguenza, Rendic. R. Accad. delle Scienze, 1876. Ball, 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 papilljB ; 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 papillae, the inner- 

 most ones largest, but in the specimen much contracted. Mouth axially 



