26 PROCEEDINGS OF THE ACADEMY OF 



The fifth or typical lumbar offers the following proportions: 



In. 



Length of body 2 7-16 



Anterior breadth 2| 



Length of diapophysis 4^ 



In. 



Breadth diapophysis distally 1 13-16 



Heiglit of canal If 



Zygapophysis to apex neural 



spine 2f 



The series of candals diminishes gradually in size to the last. 

 The dimensions of the fourth (perforated) are : 



In. 



Length body 1 3-16 



Transverse anterior diameter 2f 



Neural arch and spine If 



The neural canal is laterally compressed, or oval. The articulating ridges 

 of the epiphyses and corresponding vertebral bodies are fewer, coarser, and 

 more elevated in this species than in the augustata. In the latter they 

 are more delicate, and have a less number of complete radii. 



There are ten pairs of ribs as in the c a t o d o n, one pair less than in the 

 cone ret a. The first is destitute of the anteriorly curved angular process 

 of the c a t o d o n, but the tubercle is on an elevated base. The sixth, seventh 

 and eighth ribs are flat on the posterior face ; the last three are without neck 

 and head, and this portion of the seventh is much less than the same of the 

 sixth ; in the seventh also the angle is furthest from the tubercle. The ante- 

 terior ribs are not so dilated at the extremities as in the a u g.u status. 



In. Lin. 



First rib ; head to angle 3 5 



" " angle to extremity 5 1 



Seventh rib; length 17 10 



" " " 12 6 



The stylohyal of the specimen of this species is of relatively the same size as 

 tliat of the an gn s tat a, but is flatter, less narrowed at its anterior extremitj', 

 not swollen on its posterior border, nor constricted at its posterior extremity. 

 Its hinder border is somewhat rugose. The body and posterior hyoid cori^cra. 

 are much like those of the angustata and d e c 1 i v i s and c o o s s i f i ca-. 



In. ^, Lin. 



Length of body 2 1 



" " stylohyal 4 1 



Expanse of posterior cornua 6 6* 



The sternal pieces are separate. The anterior has been found like that ip 

 the angustata, with equally strong lateral vertical processes. The ha;ma- 

 pophyses are relatively shorter than in concreta; the fourth wants the pro- 

 duced thin anterior margin of the third, and is about the same length as tlje 

 fifth. Sixth, slender, flattened. 



In. Lin 



Length of first haemapophysis 4 8 

 Width " " (medially) 1 2 



In. Lin. 



Length fifth 6 3 



'' sixth 6 4 



" anteriorsternal segment 4 

 Breadth " " " 3 11 



The scapula is not different from that of the angustata. The brachial 

 and antebrachial elements are in this species also identical with those of .the 

 angustata; in the specimen from Upernavik the epiphysis of the humerus 

 has not coalesced, while it is eomi)letely united in that of the latter species. 

 In both the exterior (bicipital) process is more prominent and occupies a less 

 portion of the circumference than in the concreta. The humerus is also 

 much constricted in both except on the exterior aspect. 



In. Lin. 



Length of humerus 3 lU-9 



Diameter at condyle , 1 11 



" at distal articular surface 1 10-9 



Length of radius 3 3-5 



Breadth " 1 8 



Habitat, Baflin's Bay. 



[April, 



