SOME NEW DEVONIC FOSSILS 263 



allied in this respect to T. perforata Hall than to any other 

 though it differs substantially even from that. This shell has the 

 following characters : The ventral sinus is not bounded by the 

 median primary pair of plications but by the primary pair just out- 

 side the median, the latter in later growth making a pair on the 

 slopes of the wall of the sinus. Likewise the median rib on the 

 dorsal valve, while constituting the crest of the median fold is 

 accompanied by a pair of ribs of primary age which modify the 

 slopes of the fold. At the beak and continuing for one third the 

 length of the shell without modification the number of plications 

 on the ventral valve is 12, on the dorsal valve II. From this point 

 outward the ribs irregularly dichotomize into two or sometimes 

 three, fold and sinus being affected like the rest of the surface. 



The shell is transverse with straight hinge and without cardinal 

 areas. The ventral beak is abruptly perforate and the shell sub- 

 stance punctate. 



Lower Devonic. Dalhousie, N. B. 



Chonetes impensus nov. 



A large shell having the aspect of Leptostr op h i a oris- 

 k a n i a but with coarser striae. The single specimen observed of 

 this species is a ventral valve, regularly convex, with very fine sub- 



Chonetes impensus 



equal striae for about one half its length followed beyond a distinct 

 growth line by much coarser striae. Hinge margin cornute, 

 Hight 21 mm, length 28 mm. Specifically unlike any form known 

 to the writer. 



Lower Devonic. Moosehead lake, 7 miles north of Kineo, Me. 



Chonetes nectus nov. 



A small coarse ribbed species, transversely elongate in form and 

 having 14 to 16 striae, each of the larger of which is divided at 

 variable distances from the middle to the margin of the valve. It 

 is but slightly convex compared with C. hudsonicus Clarke 



