﻿ix, d. i Day: Ophiocephalus striatus 31 



the dorsal side, and the left is seen still lying in the angle of the 

 left articular (4). The ventral side is flattened, while the dor- 

 sal is somewhat conical. They lie with the median portion 

 opposite the attachment of Mackel's cartilage with the articulars 

 (4) . This name is here given because of the location. 



IV. PECTORAL AND PELVIC GIRDLES 

 PLATE X 



At the left of Plate X is the left clavicle (62), with the dorsal 

 portion of the postclavicle (77), the hypercoracoid (15), and 

 the hypocoracoid (30) attached, and seen from the inside. To- 

 ward the right is the right clavicle, seen from the outside, and 

 disarticulated. The two clavicles articulate together forward 

 and ventrally, then pass posteriorly diagonally toward the dorsal 

 side, and lie along the interior side of the interopercles (40), 

 the subopercles (13), and the opercles (14). The dorsal por- 

 tion of the clavicles is articulated with the supraclavicles (28). 

 (Plates I and X.) The dorsal end of the clavicles, which is seen 

 toward the bottom of the plate, is somewhat lamellar, but is 

 reenforced posteriorly by a considerable thickening, continuous 

 with the thickening of the middle part of the bones passing 

 upward from the ventral expanded condyles. From the middle 

 portion extends a somewhat lamellar portion, convex anteriorly 

 and concave posteriorly. Within this concavity the hypercora- 

 coid (15) and the hypocoracoid (30) are articulated. The 

 anterodorsal spinous process extends interiorly to the posterior 

 end of the supraclavicles (28). The posterior expanse or wing 

 of the right clavicle, which aids in the articulation of the hyper- 

 coracoid (15) and the hypocoracoid (30), is seen a short dis- 

 tance from the dorsal end. 



The interior side of the left supraclavicles (28) is shown on 

 the left of Plate X, while that of the right side is seen from the 

 outside. The anterior end articulates with the ventral side of 

 the body of the posttemporal (27) . The supraclavicles extend 

 backward along the inside of the opercles (14) and along the 

 outside of the dorsal portion of the clavicles (62) with which 

 they articulate. Along the inside at the dorsal margin there is 

 a fossa which looks as if formed by the rolling over of the dorsal 

 margin. The condyle at the anterior end is somewhat hooked 

 externally, as is shown especially in the bone of the right side. 

 The left is also indicated in Plate I. 



Postclavicles, lower part (6). These, as well as the upper 

 part of the postclavicles (77), are lamellar. The upper one- 



