MAZATIAJST UNIVALVES 413 



SUBGENUS AUEICULINA, Gray. 



H. fy A. Gen. vol. i. p. 233. 



In this group are deposited some shells, having the general 

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

 with the vertex scarcely bent. They are not sufficiently well 

 characterized for description. 



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



Tablet 1959 contains 3 imperfect specimens, having the 

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

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



.Sab. 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 proportion. 

 Hob. Mazatlan ; extremely rare, off Chama ; Lpool Col. 



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



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

 orange colour, with a conspicuously sinistral -vertex. 

 Hob. Mazatlan ; 1 sp. off Spondylus ; Lpool Col. 



SUBGENUS PAETHEN1A, Lowe. 



Parthenia, H. Sf 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. turritd, solutd, alba ; vertice nucleoso parvo, verticaliter 

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

 acutius angulatis, liris acutis, in adult d ix., in junior e pluribus, 



