﻿tx. d. i Day: Ophiocephalus striatus 33 



ventral articulates anteriorly with the hypocoracoid (30), the 

 next articulates with the hypocoracoid (30) and the hyper- 

 coracoid (15), and the 2 dorsal ones articulate with the hyper- 

 coracoid (15), while posteriorly all articulate with the pectoral 

 rays (29). The condyles are much thickened, being about 1.5 

 millimeters, while between them the bones are about 0.5 milli- 

 meter. The epicondyle of the ventral actinost is very thin. 

 The actinosts are found in Plate X, and are shown from within, 

 the left actinosts being at the left side. The right actinosts 

 are represented from the outside. The left actinosts may also 

 be seen in Plate I. 



The pelvic girdle (32) is united anteriorly with the ventral 

 portions of the clavicles (62) by ligaments, and is separated 

 from them a distance about two-thirds its length. The posterior 

 condyles of the two parts of the girdle are much thickened to 

 articulate with the anterior ends of the pelvic rays (33). The 

 right and left parts are shown from the dorsal side in Plate X, 

 and the left part from the left side in Plate I. 



Fig. 1. Caudal vertebra, the last but 2 (131) , anterior view. X 2. 



V. VERTEBRAE, RIBS, AND HYPURALS 

 PLATES XI AND XII 



The first 3 vertebras have no transverse processes (46, 47). 

 From the 4th to the 8th they grow longer and extend farther 

 laterally, although they immediately begin to slant ventrally, 

 so that a little posterior to the median abdominal region they 

 are almost vertical. The fossae of the transverse processes of 

 the 3d, 4th, and 5th ribs are turned dorsally, then in the suc- 

 ceeding ribs they begin to turn more and more posteriorly, 

 until in the 18th vertebra they face posteriorly. 



The first 2 vertebras, atlas and axis, receive the articulation 

 of a pair of single ribs, the succeeding 15 vertebrae the articula- 

 tion of a pair of double ribs, and the remainder, except the last 

 5 vertebrae, have a pair of single ribs articulated. 



In Plate XI the atlas (70) is seen from the posterior side 

 and slightly tilted posteriorly, showing the centrum, neural 

 arch, and neural spine. It is seen also in text fig. 2. 



The axis (87) is seen from the posterior, showing the centrum, 



123716 3 



