No. 4.] BILLINGS — FOSSILS OF NEWFOUNDLAND. 47^^ 



somewhat different. The posterior pair seem to be entirely dis- 

 connected in the middle and the next two pairs are rather more 

 curved. The maro;inal rim of the front of the head, seems to be 

 close up to, and in contact with, the front of the glabella. The 

 surface is ornamented with minutely corrugated, raised lines 

 which, in some places, anastomose so as to present an irregu- 

 larly reticulated appearance. This at once separates the species 

 from P. tenelhts, the surface of which is minutely granulated. 

 The surface of A. veinistiis is somewhat like that of this species,' 

 but the raised lines are more distant, and besides the posterior 

 glabellar furrow extends all across. The length of the most 

 perfect glabella examined is about thirteen lines. Only three 

 fragments, (all of the glabella) of this species occur in the col- 

 lection. Form of the eyes and of all other parts unknown. 

 It occurs at Chapel Arm, Trinity Bay. 



Genus Iphidea, gen. nov. 



Fig. 13. Iphidea hella; ventral? aspect. 



Of this genus we have no specimens showing the internal 

 structure, but the external characters seem sufiBcient to separate 

 it from any described generic group. The ventral ? valve of 

 J. hella., is conical, strongly elevated at the beak, hinge-line nearly 

 straight, posterior angles narrowly rounded, sides and front ueai'ly 

 uniformly rounded, forming rather more than a semi-circle. 

 Posterior side with a large false area, and a convex pseudo-delti- 

 dium, the width of which at the hinge line is nearly one-third 

 the whole width of the shell. The dorsal valve is semi-circular, 

 moderately convex most elevated at the beak. The hinge-line 

 appears to be straight. The form and structure of the posterior 

 side, (such as the area, foramen, deltidium, &c.,) cannot be made 

 out from the specimen, owing to its imperfection. The surface 

 is covered with fine concentric striae, which in the ventral ? valve 

 are continued around on the area. Of these striae there appear 

 to be from 15 to 20 in the width of one line, their size varying 

 somewhat in different parts of the specimen. There are also a 

 few obscure radiating striae. Width of ventral valve, 7 lines ; 

 length, 5 lines; height, 2 lines. 



