CHONDROPTEKYGII. 651 



filaments proceeding from these appendices, which are 

 common in the eggs of the sharks ; the shape, moreover, of 

 these is nearer to a true square than that of the sharks' eggs, 

 by which the two which are equally common on all parts of 

 our coast, and are vulgarly called sailors' purses, may be 

 easily distinguished. The ovary of the female has not a large 

 number of these eggs ; after one or two of these eggs have 

 been fecundated, the foetus continues to enlarge, until in due 

 time it is enabled to escape from the shell or husk which con- 

 tains it in the matrix of the mother, and then escapes from 

 its' parent in a perfect state, the shell or purse being expelled 

 immediately after ; a fresh fecundation then becomes necessary 

 before any of the remaining eggs are perfected, and a fresh 

 parturition is supposed to take place about once a month 

 during the summer. 



Of the Trygons, or Rays with the .tail armed, there are 

 several species, among which Ihe Common Trygon, or sting- 

 ray, (Raia pastinaca of Lin.) is the best known. This Ray is 

 roundish, or rather pear-shaped, with the muzzle nevertheless 

 slightly pointed. It is of a dirty yellow colour above, white un- 

 derneath, and does not generally exceed ten or fifteen pounds in 

 weight. It is found in considerable numbers in the European 

 Atlantic Seas, and generally wallowingin the sand or mud, espe- 

 cially in the Mediterranean. Captain Cock moreover found it 

 off the extensive coast of New Holland, and named one of the 

 bays of that immense island Sting Ray Bay, from the number 

 of these fish found there. The serrated sting on the tail it 

 possesses in common with the Myliobates or sea eagles, in 

 this respect therefore we shall speak of the two together. 



Among the species proper to this subgenus, stands the 

 Raia aquila of Linnaeus as type. This subgenus is primarily 

 distinguishable from the last, by having the head partly 

 disengaged from the pectoral fin, and by the character of the 

 teeth. The body is smooth, and the pectoral fins represent 



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