MAZATLAN UNIVALVES 413 



Subgenus ATJEICULINA, Gray. 



K. Sc A. Gen. vol. i. p. 233. 



In this ^oup are deposited some shells, having the general 

 aspect of Odostoniia3, but presenting no vestige of a plait, and 

 with the vertex scarcely bent. They are not sufficiently well 

 characterized for description. 



494. AuElCULINA , sp. ind. (a.) 



Tablet 1959 contains 3 imperfect specimens, having the 

 general aspect of O. gravida, Gould, (Cal. ^ Mex. Shells, p. 11, 

 pi. 14, f. 14, Sta Barbara.) 



Mah. — Mazatlan ; extremely rare, off Spondylus and Chama ; 

 L'pool Col, 



495. AuEicuLiNA , sp. ind. (b.) 



Tablet 1960 contains 2 imperfect specimens, white, differing 

 from the last in being much narrower in ijroportion. 



Hab. — Mazatlan ; extremely rare, off Chama ; L'pool Col. 



496. AuEicULiNA , sp. ind. (c.) 



Tablet 1961 contains a fragment, like the last, but of a rich 

 orange coloui", with a conspicuously sinistral vertex. 



Hab. — Mazatlan ; 1 sp. off Spondylus ; L'pool Col. 



Subgenus PARTHENIA, Loice. 



Parthenia, JS. 8f A. Ad. Gen. i. 233. 

 Parthenia (pars), Lowe. 



Shell with the surface somewhat strongly sculptured ; colu- 

 mella plaited. 



Section A. Shell thin, turrited, transversely ribbed. 



497. Paethenia scalaeifoemis, n. s. 



P. t. turrita, solutd, albd ; vertice nucleoso parvo, verticaliter 

 sito, pane immerso ; anfr. normalibus v. elongatis, postice 

 acutius angulatis, liris acutis, in adultd ix., injuniore pluribus. 



