44 NATURAL HISTORY. 



thin. There are half-a-dozen species from all the tropical and sub-tropical seas. The well-known 

 Pteroplatea altavela occurs in the Mediterranean and on both sides of the Atlantic. Dr. Giinther 

 includes two genera in this family which want the bony spine on the tail. One of these Ellipesurus 

 from the Rio Blanco, in British Guiana, has the tail veiy short, and distinct from the nearly 

 circular disc. The other genus Urogymnus has a long tail, and a body densely covered with 

 osseous tubercles. It is known only from the Indian Ocean. 



FAMILY VI. MYLIOBATID^E, THE EAGLE RAYS. 



The Eagle Ray* is so named on account of the broadly-expanded pectoral fins, which closely 

 resemble wings. The head projects well in front of them ; the tail is twice as long as the body, 

 slender like a whip, and, immediately behind the dorsal fin, carries a doubly-serrated spine. The 

 eyes are placed so as to look laterally, and have been compared to those of an ox. The colour of the 

 body is greenish or brown, and the skin is smooth. The palate consists of a succession of transversely 

 elongated teeth, margined at the sides with smaller teeth. Specimens of the fish in the British 

 seas have been estimated to weigh three hundred pounds, but the species is rarely taken. In the 

 Mediterranean it is much more abundant, but the flesh, though sold in the Italian markets, is not held 

 in great favour. Eagle Rays have been seen swimming on the surface of the sea, as have many other 

 species of the same group, and they appear to breast the tide without difficulty. It is probable that 

 the species is widely distributed, since it has been taken in the neighbourhood of Sydney, on the 

 Australian coast. All the other species of the genus occur in Eastern seas, especially those of China, 

 Japan, and the Indian Archipelago, though the Myliobatis bovina appears to be limited to the Medi- 

 terranean and adjacent parts of the Atlantic. In two species, both known from young specimens, the 

 caudal spine has not been observed, and Couch records that it had not yet appeared in an embryo 

 which he found still contained in the purse. He describes the purse in the British species as six 

 inches and a half long and four inches and a half broad, with tendrils at the corners which were 

 seven inches and a half long, and ended in a slender cord. The surface of the purse was marked 

 with closely-set raised longitudinal lines, which were crossed by other lines and raised points. 

 Towards the corners the reticulations form squares. The purse is nearly black. There are two other 

 genera in this family the Aetobatis, which is distinguished by having broad, flat teeth, like those 

 of the middle series of Myliobatis, without any lateral teeth ; and Rhinoptera, which has no large 

 median teeth, but has the jaw covered with polygonal plates, like a tesselated pavement. 



THE OX RAY, OR SEA-DEVIL.t 



The Ox Ray, or Homed Ray, differs from other Skates in having two processes prolonged for- 

 ward from the pectoral fins, like horns. Its pectoral fins are even more expanded than those of the 

 Eagle Ray, but on the other hand its tail is extremely short, and the dorsal fin is placed upon the 

 hinder part of the body. It is brown above and white below. Its home appears to be in the 

 Mediterranean, though specimens have been taken on the coast of Ireland. The flesh is red, 

 dense, and difficult of digestion, but is eaten by the poor. In the Mediterranean, examples have 

 been captured twenty-eight feet wide and twenty-one feet long, though this was said to be the 

 smallest of a shoal. The fish was estimated to weigh a ton. The mouth is wide enough to 

 swallow a man. The females are said to be larger than the males, and darker in colour. The 

 young are produced in September, from eggs contained in long yellow cases. The species feeds 

 chiefly upon Cephalopods and Fishes, and has been taken in nets arranged to catch the Tunny. 

 The liver is large, and yields a quantity of oil. Dr. Giinther describes the teeth as minute, 

 extending nearly to the angles of the mouth, and arranged in more than a hundred and fifty 

 rows. The number of rows of teeth is distinctive of the species. One with forty rows in the upper 

 jaw occurs on the coast of Brazil, and others with from thirty-four to ninety rows occur in the 

 Indian seas, and one species ranges to Japan. In the nearly-allied genus Ceratoptera which 

 differs in having the teeth developed in the lower jaw only an equally large size is apparently 

 attained, for the Ceratoptera vamjryrus, which frequents the Atlantic and Gulf of Mexico, attains a 

 width of twenty feet. A specimen fifteen feet wide, and as long, was between three and four feet 



* Myliolatts aquila. f Dicerolatis yiorna. 



