V W89."'] PROCEEDINGS OF THE NATIONAL MUSEUM. 275 



This curious little shell is probably the same as Conrad's Miocene 

 fossil ; at all events it is fossil in the Miocene. I have received it under 

 the name of Jlontacuta lirulata Carpenter, from the West Indies. It is 

 yellowish, sometimes radiated with red, closely concentrically waved 

 and quite compressed. It differs from most species of Semele in its 

 small size and erect beaks, but in nothing else so far as the shell is 

 concerned. Semele caneellata, both in size and attitude of the umbones, 

 forms a transition from this little member of the group to the ordinary 

 type. 



Order ANOMALODESMACEA. 

 Suborder ANATINACEA. 



Family AXATINIDiE. 

 Genus ASTHENOTHiERUS Carpenter. 



Subgenus BUSHIA Dall. 

 Bushia (elegans var ?) Panamensis Dall. 



Shell resembling B. elegans in all respects except that the single 

 valve collected is proportionately higher, the umbo more central, the 

 auterior end more evenly rounded and the posterior end shorter and 

 more vertically truncate. Maximum longitude of (right) valve 14 ; alti- 

 tude 11.3; (semi) diameter 4; vertical of beaks behind auterior end, 8 mm . 



Hab. — Station 2805, in 51 fathoms, mud, in Panama Bay. 



It is very interesting to find Bushia on the west coast as Astheno- 

 thcerus was found in Florida, each having first been described from the 

 opposite shore of the continent. 



Genus THRACIA Blainville. 



Thracia distorta Montagu*. 



Thracia distorta Montagu, Dall, Bull. Mus. Comp. Zool., xn, p. 307, 1886; List of 

 Marina Mollusks, U. S. Nat, Mus. Bull., 37, p. 64. No. 383, 1889. 



This species has already been reported from Honduras as well as 

 European seas, and was collected by the Albatross at Station 2764, in 

 11£ fathoms, sand, off the Rio de la Plata. 



Thracia Stimpsoni Dall. 



Plate xiii, Fig. 2. 

 Thracia Stimpsoni Dall, Bull. Mus. Comp. Zool., xn, p. 307, 1886. 



This fine species was collected by the Albatross in 28 fathoms in the 

 Gulf of Mexico, on the line between Tampa and the Dry Tortugas, at 

 U. S. Fish Commission Station Xo. 2410. Its nearest relative is T. 

 convexa Wood, from which it differs in proportions and sculpture. With 

 the exception of the northern T. Conrarfi, it is the largest American 

 species. 



