392 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



straight ; pallial sinus deep ; valves soleniform, truncate behind and rounded in 

 front ; teeth lamellar, the posterior series much elongated, few in number. 



Unless the differences, when all the characters of Phaseolus ovatus are known, 

 prove greater than now appears, Silicula can hardly rank higlier than as a sub- 

 genus of Phaseolus, especially if, as seems likely, species intermediate in form 

 should turn up. 



Phaseolus (Silicula) patagonicus Dall, n. sp. 



Shell small, thin, elongate-oval, very inequilateral, anterior side shorter, 

 anterior end rounded, anterior dorsal slope nearly straight ; posterior slope very 

 slightly curved and descending ; posterior end bluntly rounded, not truncate, not 

 emarginate, slightly smaller than the anterior end ; outer surface smooth except 

 for faint incremental lines, covered with a thin, polished, pale olive periostracum ; 

 beaks (eroded) ; a well-marked internal pit under them ; anterior hinge line with 

 two short horizontal teeth ; posterior with four elongate, straight, overlapping 

 lamellae ; interior of the valves white, porcellanous, with a large pallial sinus 

 rounded behind, not very deep ; muscular scars small ; on the disk inside of the 

 pallial line, extending backward and upward from the anterior adductor scar, is 

 a series of somewhat irregular but more or less continuous small scars which 

 enclose a large oval area of which the upper boundary is the hinge line, and 

 which reaches back to about the middle of the shell. Length, 8.4; anterior end, 

 2.0; alt. 4.2; max. diam. 1.8 mm. 



U. S. S. " Albatross," station 2783, on the west coast of Patagonia, southern 

 Chile, in S. lat. 51° 2', in 122 fathoms, mud, bottom temperature 48° F. U. S. N. 

 Mus. 96,914. 



Only a single valve of this species came to liglit, the umbo being eroded, but 

 the characters are abundantly sufficient to separate it from the North Atlantic 

 species. 



Arcacea. 



Limopsidae. 



LIITIOPSIS Sasso. 



Limopsis Sasso, Giorn. Ligustico, di Sci. Let. ed Arti, Genova, 1827, 1, p. 476; type, 



Area aurita Brocclii,yi(/c Sacco. 

 Pectunculinn Orbigny, Pal. Franc. Terr. Cret., 1844, 3, p. 182 ; 1st species, Pectunculus 



scalaris Sowerby. 

 Trigonocaelia Nyst et Galeotti, Bull. Acad. Sci. Bruxelles. 1835, 2, p. 289; Ist 



species, Pectunrulus grannlnlns Laninrck. 

 Felicia Mabille et Uocliebrune, Miss, du Cap Horn, Moll., 1880, 6, p. H 115, sole ex. 



F. jounsraumei M. & R., p. H 110, i)l. 7, flg. 9a-b. 

 CoBtnetopii Uovereto, Note prev. Pelecip. Tongr. Lig., Atti Soc. Ligust., 1898, 



9, p. 177 ; type, Limopsis reti/era Semper. 



