257 



apex, the shell must be at least one inch from the siphuncle on the dorsal 

 side ; and, as the specimen is mutilated on that side, the distance may be 

 greater. The septa are excessively thin, and at their junction with the 

 siphuncle are curved towards the apex, forming an attachment similar to 

 that observed in the ordinary species of Orthoceras and Nautilus. 



In a specimen 30 lines in length, the dorso-ventral diameter at the larger 

 extremity is 14 lines ; lateral, 11 lines , at li inches nearer the apex, 

 the dorso-ventral diameter is 11 lines, and the lateral, 9 lines. Thence 

 more rapidly tapering to the apex. In the first 18 lines there are 12 

 septa or 8 to the inch on an average, but in the apical inch there are 12 

 or 13. In other specimens they are a little closer together. 



In P. Oanadense the siphuncle is in general, more curved, and the 

 septal ridges cross it, sloping from the dorsal side downwards in proceeding 

 to the ventral side. In this species they slope in the opposite direction 

 (assuming always that the most curved side is the ventral). 



Dedicated to A. H. WORTHEN, State Geologist of Illinois. 



Locality and Formation. H. Port aux Choix, Newfoundland ; Quebec 

 group. 



Collector. J. Richardson. 



PILOCERAS TRITON. (N. sp.) 



Description. Larger than P. Canadense, with a straighter siphuncle 

 and more distant septa. 



The best preserved siphuncle collected, is 5J inches in length ; dorso- 

 ventral diameter, at the larger extremity 2 inches ; lateral 21 lines ; in 

 the apical 18 lines, there are 10 septa ; in a length of 2 inches next the 

 large end, there are only 7. 



In P. Canadense, where the lateral diameter is 12 lines, there are 7 

 septal rings on the siphuncle, but in this species at the same diameter 

 there are only 5, and further up they are 3J- lines distant from each other. 



Locality and Formation. H and I, west side of Pistolet Bay, New- 

 foundland ; Quebec group. 



Collector. J. Richardson. 



PILOCERAS GRACILE. (N. sp.) 



Description. This name is proposed for a species, of which a portion 

 only of a siphuncle has been found. It differs from all the others in being 

 proportionably more slender and elongated, and in having more distant 

 septa. 



