30 
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 Nofhosaurus 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 Pistosaiirm 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, subcoinpressed 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 PI. 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 
