688 ON THE FIN-SKELETON OF BATOID FISHES. [DcC. 2. 



in the forward and downward slope of its anterior border. Whereas 

 in the Sharks the vertical diameter of this cartilage is greatest at its 

 middle, or near its posterior extremity, in the Chimseroids it is 

 greatest at its anterior end ; and in some respects the anterior border 

 of the Chimaeroid metapterygium repeats, in its relationships to the 

 propterygium, the conditions of the mesopterygium of the Selachii. 

 In its realization of these characters, and in the simple constitution 

 of its cartilaginous rays, the pectoral metapterygium of Squaloraja 

 closely resembles that of the living Holocephali ; and, on careful 

 comparison of the two, I am convinced that, with respect to the 

 skeleton of its paired fins, that fish is indubitably, and as Dr. 

 Giinther at first suggested \ a Chimaeroid. 



In talking this matter over with Dr. Traquair during the autumn 

 of 1889, I was much rejoiced to find that he had independently 

 arrived at the same conclusion on a study of the skull, which he 

 asserts^ is "of the autostylic structure." It is to be hoped that he 

 will give us, with as little delay as possible, fuller details of this 

 important discovery. 



My best thanks are due to my friend Mr. Smith Woodward, for 

 his courtesy in having allowed me to examine bis matchless specimen. 



' Geol. Mag. vol. ix. (p. 148). Curiously enough he altered his mind later, in 

 doubtfully referring it (' Introduction to the Study of Fishes,' p. 335) to the 

 Pristiophoridcs. 



^ Nicholson & Lydekker's Manual of Palaeontology, vol. ii. p. 950 (1889). 



