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FOSSIL REPTILIA OF THE 



palatine (20), and laterally to join the maxillary (21), of which a fragment is preserved 

 in this crushed specimen. The lower opening of the temporal fossa is bounded 

 mesially in nearly equal proportions by the pterygoid and ectopterygoid. 



Estimating the length of the skull in the present specimen at two feet, about six 

 inches in length of the hind part is here preserved ; and the palatal nostrils open 

 chiefly upon the hinder half of this part. In their posterior position, therefore, they 

 agree with those in Teleosaurus, but differ in being divided by the medial productions 

 of the palatines and pterygoids, and in not being confluent, as a single aperture, as in 

 the Crocodilia ; thus they exemplify the more general Reptilian character as it is 

 preserved in our modern Lacertilia. 



In the Nothosaurus the palatonares are two ; but they open upon the anterior 

 fourth part of the bony palate, having their hinder boundary formed by the palatines 

 instead of their front one. In Pistosaurus the palatonares are situate about midway 

 between the fore and back part of the long and narrow bony palate. In all 

 Sauropterygia the pterygoids present much of their crocodilian character in their 

 posterior extension and expansion, underlying the posterior cranial centrums and 

 covering, in this way, in Plesiosaurus, more of the basi-occipital than in the crocodiles. 

 Some portions of long, slender, subcompressed bones adhering to the present instruc- 

 tive fragment of the plesiosaurian cranium may have belonged to the hyoidean arch ; 

 one of them (40) adheres to the bony palate, and partly conceals the left palatal 

 nostril in fig. 2. 



Pectoral and pelvic arches and limbs (Tab. IX). 



The scapula (Tab. IX, 51) is 5 inches in length; smooth and convex externally at 

 its narrow upper part, where it shows a breadth of 10 lines; it rapidly expands to a 

 breadth of 3 inches at its humero-coracoid extremity, which overlaps, as before 

 mentioned, the head of the dislocated humerus. The outer surface of the articular 

 end of the scapula is roughened by longitudinal ridges. 



The humerus (ib., 53), showing a breadth of I inch 9 lines where it emerges 

 beneath the scapula, expands to a breadth of 4 inches where it is articulated to the 

 antibrachial bones ; its anterior border is straight, less convex at the distal half than 

 in PI. dolichodeirus ; less expanded at the distal end than in PL homalospondylus. 



The radius (ib., 54) is 3 inches 2 lines in length, 2 inches broad at its proximal end, 

 1 inch 9 lines at its distal end ; with a thin, straight, somewhat irregular anterior 

 border, and a thicker, smooth, concave posterior border. The ulna (ib., 55) presents 

 the usual reniform figure, with the concavity toward the radius ; it is of the same 

 length as the radius, but is flatter ; 2 inches 3 lines across its middle part ; the 

 margin next the radius is rather more concave than that which it opposes ; the 



