160 CONTRIBUTIONS TO CANADIAN PALEONTOLOGY. 



LAMBLLIBEANCHIATA. 



Ctpkina Yukonensis. (N. Sp.) 



Plate 21, fig. 4. 



Shell rather small, compressed convex, inequilateral : marginal out- 

 line varying from subcircular or ovately subcircular to subovate, the 

 height in the majority of specimens being very nearly as great as the 

 length. Anterior side short and rounded : posterior side longer and 

 somewhat obliquely subtruncated at its extremity : ventral mai-gin 

 longitudinally semiovate, rounding upward rapidly in front and 

 straighter behind : superior border sloping dovs^nward very gently be- 

 hind the beaks and descending abruptly and coi cavely in front of 

 them : beaks broad, prominent, appressed, placed in advance of the 

 mid-length, and curved obliquely forward : posterior umbonal slopes 

 sometimes distinctly angulated, but, as this character is seen in only 

 one sjjecimen, it may be the result of distortion. 



Surface marked by concentric lines of growth. Hinge dentition and 

 muscular impi'essions unknown, though the pallial line appears to have 

 been entire. 



Dimensions of one of the most perfect specimens collected : maximum 

 length, thirteen millimetres ; greatest height, twelve mm. 



One somewhat crushed left valve, with the whole of the test pre- 

 sei-ved, two perfect and well preserved casts of the interior of the same 

 valve and three similar casts of the right valve. 



This species is rather variable in shape, and seems to bo most nearly 

 allied to the Cyprina Marcousana of de Loriol, from the Middle Neo- 

 comian of Switzerland. 



CEPHALOPODA. 



SCHLOENBACHIA BOREALIS. (N. Sp ?) 



Plate 21, fig. 5. 



Perhaps a variety of Schloenbaclda propinqua. 



Cfr. Schloenhackiapriipinqua, Whiteaves. 1884. Gaol, and Nat. Hist. Surv. Can., 

 Mesoz. Fobs., vol. I., p. 247, pi. 33, figs. 2, 2a, 2b, 

 2c. 



Shell compressed at the sides, its periphery encircled by a flattened, 

 thin and very prominent simple keel, which attains to a height of 



* See Piotet. andCampicbe'sPal^ont. Suisse., Foss^. duTerr. Cret. des Envir.de Ste. Croix, Ser. 

 3, p. 214, pi. 113, figs. 3 and 4. 



