48 Annals of the Carnegie Museum. 



Through the kindness of Curator Henshaw of the Museum of Ccjm- 

 parative Zoology we are able to present figures of the fine fossil which is 

 the type of this species. The species has not previously been figured 

 and has therefore been confused with Bathyurns extans. In B. Jongispinns 

 the glabella is more pustulose, the brim^ is wider and less conca\e, and 

 the genal spines longer than in B. extans. The pygidia of the two species 

 are quite different, that of B. extans being long and roughly triangular, 

 while that of B. longispinus is nearly semicircular in outline, short and 

 wide, and with a rather wide concave margin. The axial lobe of the 

 pygidium is also shorter in this species than in B. extans, and has only 

 two rings on the anterior end. 



The cephalon of the type is 26 mm. long, measured along the axis to 

 the back of the neck-ring, and 50 mm. to the tips of the spines. The 

 pygidium is 13 mm. long and 25 mm. wide. 



The fragment of a pygidium from the lower part of the Trenton of 

 New Jersey which Weller described as Ptychopyge jerseyensis was very 

 kindly loaned by Mr. Henry B. Kummel, State Geologist. It proves to 

 belong to the genus Bathyiinis, and while hardly specifically identifiable, 

 its short wide form and its geological position indicate that it is B. longi- 

 spinus. 



Locality. — This species is rather common in the Black River at Newport, 



New York, but has not been reported elsewhere, perhaps because it has 



been identified as Bathyurus extans. It is not surely known to occur at 



Ottawa. 



Bathjmrus spiniger (Hall). 



Plate XV, figures 4-6. 



Acidaspis spiniger Hall, Paleontology New York, I, 1847, 241, pi. 64, fig. 5, 

 Bathyurus spiniger Clarke, Paleontology of Minnesota, III, ii, 1897, 723, figs. 

 38-40. — Raymond, Bulletin American Paleontology, III, 1902, pi. 19, figs. 1-3. 



In the Black River at Ottawa Bathyurus extans is replaced by Bathyurus 

 spiniger, a species which ranges from the upp^r part of the Lowville to 

 the middle of the Black River. 



The glabella is very convex, covered with sharp tubercles, and the neck- 

 ring bears a short stout spine which projects upward and backward. On 

 young specimens there are two pairs of glabellar furrows whose direction 

 is at almost right angles to the axis of the glabella. The furrows can be 

 found on adults, but they are exceedingly faint. The eyes are lar;e, the 



'This term is proposed by Bather for the flattened border on the cephalon of 

 Harpes. {Revisla Italiana di Paleonlologia, 1910, 4.) 



