l.ONG-XOSlil) SKATK. 417 



eye and temporal orifice on each side, and the regular rows 

 of spines towards tlie upper outer surface of the pectoral fins. 

 The elongation of the central teeth, the development of the 

 eylintlrical appendages, and the appearance and growth of the 

 clusters and rows of spines on the upper surface at the parts 

 pointed out, may be considered analogous to those sexual 

 distinctions which exist in many species of birds and mam- 

 mals, and which have been called by John Hunter and 

 others, secondary sexual characters. These spines on the 

 upper surface of the males occur in the different species of 

 Skate with smooth skins, as well as in the others, and are 

 entirely independent of those spinous productions of the 

 cuticle which distinguish two British species, and will be 

 more particularly noticed hereafter. It may here be stated 

 generally, that the Skate are very voracious : their food con- 

 sists of any sort of fish that they can catch, with mollusca, 

 testaceous or naked, and Crustacea. So powerful are their 

 muscles and jaws, that they are able to crush the strong shell 

 of a crab with ease. As in the Sharks, the females are 

 larger than the males. 



The under surface of the Skate at the head of this subject 

 presents two central circular cavities. The upper one just 

 below the transverse mouth is bounded laterally by the five 

 branchial apertures on each outside ; within this cavity the 

 gills arc placed. The circular cavity below is the abdomen, 

 and contains the stomach, intestines, and other viscera. The 

 heart is placed immediately in the centre between the two 

 cavities, and is protected by a broad and strong transverse 

 cartilaginous arch, the situation of which is indicated. 



The young are produced toAvards the latter part of spring, 

 or during summer. They arc deposited by the parent 

 fish in thin horny cases, like those of some of the Sharks 

 already described ; but they arc more square in form, as 



