BY WILLIAM A. HASWELL, M.A., B.SC. 107 



The cephalic fin consists of two curved cartilaginous styles 

 connected with the skull as above noticed, having a series of short 

 irregular rays attached along their anterior border, and of a series 

 of irregular rays between them. The latter are not directly connected 

 with the skull, and do not form a rostral prolongation of it as in 

 Torpedo . 



Pelvic Fins. (Plate II., fig. 9.) 



The pelvic arch is a straight, rather narrow bar, continued 

 externally into a pair of long, pointed, lateral processes directed 

 forwards and outwards. The axial cartilage of the fin is narrow 

 and pointed. Nearly all the fin-rays are bifurcate. The anterior 

 rays articulate directly with the pelvic girdle, the first being shorter 

 than the rest and repi'esenting the pre-axial fin-ray ; there is no 

 basal cartilage representing the mesopterygium. 



There are two distinct dorsal fins of about ten to twelve rays 

 each, placed close to one another on the short tail. The caudal 

 fin itself is very small. 



TRYGONORHINA FASCIATA. 

 Plate II., Figs. 1-5. 



Vertebral Column. 



The antei^ior vertebral plate presents a very strong odontoid 

 process with a crescent-shaped articular surface at its extremity, 

 and at the base of the odontoid process two concave articular 

 surfaces for the occipital condyles. The spinous processes of the 

 anterior vertebral plate are combined into a very prominent mesial 

 ridge, and the transverse processes are likewise amalgamated, as in 

 Rays generally, and develope about the middle of the length of the 

 plate on either side a strong vertical process which reaches nearly as 

 high as the spinous ridge. The spinous ridge ends some distance in 

 front of the hinder extremity of the vertebral plate, and behind it 



