294 

 Arca (Nemodon) Cumshewensis. (N. Sp.) 



Grammatodon inorrmtus, Whiteaves. 1884. This volume, pt. 3, p. 235, pi. 31, figs. 8, 

 8, a-b. But probably not G. inornatus of Meek and Hayden, 

 (1858) which is said to be a Jurassic species. 



Shell, or rather cast of the interior of the shell, small, moderately con- 

 vex, about one-third longer than high, inclusive of the beaks, and very 

 inequilateral. Anterior side shorter than the posterior : anterior end 

 angular at its junction with the cardinal margin above, rounded and nar- 

 rowing rapidly inward and downward to the base below : posterior end 

 obliquely subtruncated above, slightly produced and rounded more or less 

 narrowly, in some specimens obtusely pointed, below : ventral margin (or 

 base) nearly straight or but very gently convex for the greater part of its 

 length : superior border, behind the beaks, straight and almost parallel 

 with the ventral margin : umbones broad and moderately prominent, 

 beaks curved inward and forward, placed in advance of the midlength : 

 posterior area tolerably well defined in some specimens but not in others. 



Test unknown : surface of well preserved casts of the interior of the 

 shell marked by numerous, closely disposed, minute concentric stria? and 

 by minute, obscure, radiating raised lines. Hinge dentition not well 

 shown in any of the specimens known to the writer, but in one of the 

 casts there are distinct impressions of two or three longitudinally 

 elongated posterior teeth, parallel to the hinge line, in the left valve. 



The six specimens collected at Cumshewa and Skidegate inlets by Dr. 

 G. M. Dawson in 1878 and referred to on page 235 of the third part of 

 this volume, are the only ones that the writer has seen. 



CUCULL.EA PONDEROSA. (N. Sp.) 

 Plate 38, figs. 1 and la. 



Cueullcea (?) Sp. Undt. Whiteaves. 1876. This volum«, pt. 1, p. 73. 



Cucullcea (Tdonearca). Species undeterminable. Whiteaves. 1884. Ibid., pt. 3, p. 235. 



Shell large, ventricose, subtrapezoidal and very inequilateral : valves so 

 strongly convex in the umbonal region that their maximum breadth or 

 thickness, when closed, exceeds their greatest height, inclusive of the 

 beaks : test thick. Anterior side short : anterior end angular above, at 

 its junction with the cardinal margin, and broadly rounded below : 

 posterior side broader and a little longer than the anterior : posterior end 

 obliquely truncate above and obtusely pointed below. Ventral margin 

 curved rather convexly in advance of the midlength, straighter behind : 

 superior border nearly straight, ascending slightly and very gradually 

 from the anterior to the posterior end : umbones prominent, broad and 

 rather obtuse : beaks widely distant, depressed, curved inward and a little 



