446 Dr. Bancroft on the Sea-Devil of Jamaica. 



" appearance of having two horns *." But if the specimen before us may 

 serve to direct our judgment, the description just cited will be found to 

 convey a very wrong notion concerning both the origin and the form of 

 the part which has been adopted as characteristic of the genus. So little 

 connected are these processes in reality with the pectoral fins, that a space 

 of not less than fifteen inches intervenes between their respective roots, 

 which space is occupied by the anterior edge of the thorax. The pro- 

 cesses arise from, and are articulated with, a thick straight cartilage, 

 nearly answering to the os mate in the human subject, which extends 

 somewhat obliquely downwards and backwards, from a little before the 

 angle of the mouth, across to the edge of the thorax, four or five inches 

 behind the eye. They measure about twenty-one inches in length, nearly 

 a foot in breadth at their origin, nine inches across the middle, and an 

 inch in thickness, and terminate in a sub-oval flap, nearly flat on the 

 under surface, but strengthened on the upper by a strong ridge of carti- 

 lage, ten or twelve inches long, which projects from near the eye, forms 

 the interior edge of the flap, and gradually tapers into it. They consist 

 of a broad layer of longitudinal cartilaginous ribs, or rays, covered on 

 each side with muscular fibres, and inclosed by the common integument. 

 Between their bases a void semicircular space intervenes, whose diameter 

 measures twenty-five inches, while their ends recede a little froin each 

 other. 



Similar as these appendages appear to be in structure to the pectoral 

 fins of the same animal, there seems reason to think that they are not in- 

 tended to serve the ordinary purposes of fins. Their exterior edge and 

 their extremity are the only parts of them which are flexible, the firm 

 ridge on their upper surface restricting them from being moved either 

 dovrawards or backwards, the only movements likely to aid in propelling 

 the body forwards. But this ridge will allow them a considerable extent of 

 horizontal motion ; and if the situation, and form, of the flaps be con- 

 sidered in relation to the breadth, make, and bulk of the fish, they seem 

 much more likely to impede, than to assist, his advance, whenever brought 



t The Abbe Bonnaterre, in his description of Raia Mobular (Ichthyologie, 

 page 5,) has called these appendages ears, and likened them to the ears of a 

 Bat, " Deux grandes oreilles saillaiites comme celles de la Chauve-Souris." 



