Same to posterior extremity.... 5 10 

 Floor canal to zygapophysis.... 2 9 

 Zygai)opliysis to apex of neu- 

 ral spiue 4 1 



NATURAL SCIENCES OF PHILADELPHIA. 29 



tally, anteriorly, as in angustata and cone r eta. The diapophysis of 

 the first is obliquely truncate, and furnishes a ligamentous attachment to the 

 angle of the last rib. 

 Its dimensions are : 



In. Lin. i In. Lin. 



Length body 3 6 



Anterior transverse diameter... 2 10 



Height of canal 2 1 



Width do. at diapophyses.. 1 10 

 Epiphysis to anter. extrem. of do 4 7 



Of the caudals, the last five are transverse. 



The dimensions of the fourth perforated are as foUovrs : 



In. Lin. 



Length of centrum 2 9 



Transverse anterior diameter 3 4 



Neural arch and spine 1 10 



Hcemal arch and (very low) spine (from centrum) 1 7 



" " length 1 10 



Diapophysis projection 8 



The neural canal is compressed. 



The radiating ridges of the epiphysial articulations on all the vertebrae are 

 very coarse and much broken up into mammillae. 



The coossified body and lesser cornua of the os hyoides do not resemble those 

 of the angustata as much as the latter do those of the r h i n o d o n. The 

 body is not so long as its greatest breadth, and the surface articulating veith 

 the cornua the shortest of all. Viewed from below, the posterior area is one- 

 half the anterior (equal in angustata) has a heavy double posterior margin, 

 and is marked by a median process. The cornua are of nearly equal width 

 throughout, and not expanded on the margins. Their proximal extremities 

 would have a trigonal section, owing to their inferior thickened angle. 



In. Lin. 



Length body 3 1 



Breadth " 3 7 



Length of cornu 3 7 



Expanse of cornua 8 9 



There are eleven ribs, of which the three posterior have no head, and the first 

 articulates by head with the seventh cervical vertebrae. The first, like that of 

 B. angustata, has the tubercle on a backward curved process. The superior 

 half of the shank of this rib is thin and expanded on its outer margin, while 

 on the lower half it is obliquely flattened. The ribs from the second to the 

 fifth are considerably dilated distally ; the posterior aspects of sixth, seventh 

 and eighth are rounded. 



In. Lia. 



First rib ; head to base of angular process 1 10 



" length of " " 8 



" base of process to dist. extremity 7 10 



Seventh rib; length 24 5 



Last " " IG 10 



Seven pairs of ribs are attached to bony haemapophyses, of which five pairs 

 articulate immediately with the sternum. The first is smooth, flat, and di- 

 lated distally; the second narrower and thickened distally ; the third is dilated 

 and sharp edged on the middle of the anterior border. The penultimate has a 

 slight curvature, and the last is cylindrical and very slender. The sternum is 

 yet distinguished into three principal pieces, the last narrowest and longitu- 

 dinally divided. The articular cavities are at the sutures except the two an- 

 terior, which are close together at the front of the anterior piece. The latter 

 has a cordate anterior outline, no cornua, and a convex posterior suture. 



1869.] 



