370 AXMALS OF THE CaRNKGIF MuSKUM. 



Df.scriptiox. 



Olabella convex, the highest part along the median line. Sides 

 nearly parallel, expanding a trifle toward the front. Broadly rounded 

 in front. There are three pairs of glabellar furrows which are not 

 deeply indented. The posterior pair turn back and run nearly to the 

 neck ring. Neck segment narrow, the furrow in front of it sharp and 

 not deeply impressed. Eye lobe small, situated beside the posterior 

 half of the second glabellar lobe and the anterior half of the third 

 lobe. Fixed cheek small, triangular, and extending to the genal angle. 

 Surface finely papillose. 



Measurements. — A cranidium : length 7 mm.; width 13 mm.; 

 width of glabella, 6 mm. 



This species differs from Clieirurus prolificus Billings, in only two 

 particulars. The glabella of that species tapers toward the front, 

 while, in our species, it is as wide or wider at the front than at the 

 neck segment. The posterior pair of glabellar furrows in C. prolificus 

 make a sigmoid curvature, while, in our species, they turn back sharply 

 at their posterior ends. 



Locality. — Sloop Bay, Valcour Island. 



Pseudosphaerexochus chazyensis sp. nov. (Plate 14, figures 19, 20.) 



In certain layers are occasionally found small glabellar which may, 

 at first glance, be taken for Spiicerexochus parints, but a closer exam- 

 ination shows them to belong to the subgenus Pseudospiicerexochus. 

 All the specimens, so far found, are glabellos, and all are of small 

 size. They occur mostly in the lower layers of the Chazy, nearly 

 always associated with Harpina antiquatus. 



Description. 



Glabella small, very convex, tapering rapidly toward the front. 

 There are three pairs of glabellar furrows, the first two pairs, short, 

 and almost parallel to the neck furrow ; the i)Osterior pair slant back- 

 ward little at first, but, as they get higher on the glabella, turn 

 abruptly backward and reach nearly to the neck furrow. Surface 

 covered with small papill?e. Neck ring narrow and convex. The 

 largest specimen in the collection differs from the others in having 

 only two pairs of glabellar furrows. 



Measurements. — -Largest glabella: 6 mm. long, 5 mm. wide. An- 

 other is 3 mm. long, 2.5 mm. wide. 



