20 BULLETIN OF THE 



fluent -with the shell throughout its entire length, and attached to the sep- 

 tum a short distance in front of the transverse plate, and running up on 

 the sides of the thin part of the septum for a short distance. Area behind 

 the lamina; much thickened for the muscular impressions, excavated be- 

 neath the lower edges of the transverse septal plate. Hinge margin as 

 wide as the shell, deeply grooved for the reception of the teeth of the 

 neural valve. 



Neural valve convex, with a straight hinge margin and broad area. 

 Foramen usually much eroded ; deltidia rudimentary, widely separated ; 

 hinge teeth strong. Interior of the valve with a low well-marked septum, 

 rounded, broadest near the middle of the valve, where its upper edge is 

 somewhat excavated ; extending from the edge of the foramen to the an- 

 terior border of the shell, where there is a slight indentation. Length of 

 the shell .15 inch, width .18 inch. 



This shell, of which a moderately large series was obtained, has a gen- 

 eral resemblance in form to C. Schrammi, but has a greater number of 

 ribs, wants the smooth mesial area, and is of a totally different coloration, 

 being scarlet with pale yellow ribs, while Schrammi is figured of a rufous 

 brown, paler on the beaks. There are some discrepancies between the 

 figure and the description of C. Schrammi, and, in spite of the apparent differ- 

 ences, I do not feel confident that the shells before me, and those described 

 by Crosse and Fischer, are more than varieties of one species. The form 

 of the septum and the transverse lamina at once separate the Coast Sur- 

 vey shells from any other species, but of C. Schrammi, unfortunately, the 

 apophyses are not figured. I have, therefore, indicated the present form 

 under a provisional varietal name, which will serve to distinguish it until 

 more exact knowledge is attained. I should add that the scarlet color is 

 not distributed in solid rays, but, under a lens, appears in concentric lines 

 transverse to the ribs and broadest in the interspaces. 



The examination of the soft parts of this species added nothing new. 

 It appeared to resemble the next species in" every particular. The ovaria 

 were three-branched in the neural valve. The size and extent of the 

 transverse plate of the septum varied in different specimens. 



Cistella (l Barrettiana var.) lutea. 

 11 Arc/iope Barrettiana Dav., P. Z. S., February, 1866, p. 103, pi. xii, fig. 3. 



= Cistella Barrettiana Dall, Am. Journ. Conch., VI, p. 146, 1870. 

 ? 1 Arm'ope Antillarum Crosse and Fiscuer, Journ. de Conchyl., XIV (3 mo Se'r. 



VI), March, 1866, p. 270, pi. viii, fig. 7. = Cistella Antillarum Dall, 



Am. Journ. Conch., VI, p. 146, 1870. 

 Tortugas, 30-43 fathoms, Pourtales. Northeast coast of Jamaica, 150 



fathoms, Barrett, Dav. Guadaloupe, W. I., 200 - 250 fathoms, Crosse 



and Fischer. 



