lot 



plate 312 of the Atlas to Volume IJl. of the •' Ten-aiiis CnHae^s;' which 

 i^s described as a cast of G. fibrosa, viewed at the buccal side, the left 

 valve is unquestionably represented as the larg-est. 



It is, however, only proper to add that in an adult specimen of C. 

 glabra figured b}- D'Orbignj^ the length is one-thi.d greater than the 

 height, whereas in C. truncata and C. 2\ebra6cenm the height and length 

 are often nearlj^ equal, and in the most elongated specimens of the latter 

 yet collected, the length is only one-sixth greater than the height. 



Mytilus pauperculds, Gabb. 



Mylilus yaiqierculus. Gabb. — Pal. Cat., Vol. I, p. 183, pi. 25, fig. 165. 



Compare M. subarcuatin', Meek k Hayden. — See Meek's Rep. on Inv. Cret. & 



Tert. Foss. U. Miss. Co., p. 69, pi. 38, 



figs. 2ff, b. 



Sucia Islands, in Division A ; J. Richardson, 187-i. A single right 

 valve, rather more than half-an-inch long. The specimen is higher and 

 not quite so much elongated as the California shell figured b}^ Gabb, but 

 probably belongs to the same species. 



MODIOLA ORN'ATA, GaBB. 

 Modiola ornaUi, Gabb.— Pal. Cal., Vol. I., p. 184, pi. 24, fig. 166. 



K". W. Side of Hornby Island, in Division D, and at the Sucia Islands, 

 in Division A ; J. Richardson, 1871-74. A small and imperfect valve from 

 each localitj'. Closely allied to Modiola pedernalis. Roemer, from the 

 Cretaceous rocks of Texas, but the two species may be easily distinguished 

 by the position of the beaks, which are terminal in M. pedernalis and sub- 

 terminal in J7. ornata. Both belong to Swainson's sub-genus Brachy- 



dontes. 



Pi.xna calamitoides, Shumard. 



Plate 20, figures 1, 1« and 16. 



Pinna calamitoiJes, Sbnmard. — Trans. Ac. Sc. St Louis, 1858, Vol. I., p. 124. 



"Shell elongated, triangular, compressed, slightly ciirved, iimbones 

 rounded ; buccal portion attenuated ; ligament margin acute, arcuate ; 

 pallial margin gently concave; surface marked with about fourteen 

 slender, rounded, longitudinal ribs, separated by much wider spaces than 

 the ribs. On the ligamental side of the shell these ribs are quite distinct, 

 regular and nearl}' equidistant, but on the j^allial portion they are ])ar- 

 tially effaced and assume the form of irregular and rather broad folds." 



"Dimensions. — Apicial angle. 28° ; at the distance of about two inches 

 from the point of the beak the width is 13 lines, and the thickness 6 

 lines." 



