THE SKATE. 



THE SKATE (Raja bails). 

 THE THORNBACK (R. clavata). 

 THE HOMELYN RAY (R. maculatd). ! 



A. THE SKELETON. 



I. THE skeleton of the skate is mainly cartilagi- 

 nous, being hardened only by a superficial de- 

 posit of calcific matter, and in the vertebral 

 column by internal laminae of the same material. 

 It is best prepared by immersing the fish, after 

 removal of the viscera, for a few seconds in hot 

 water a few degrees below the boiling-point. This 

 process softens the muscles and ligaments, and 

 allows of their being readily stripped off the 

 cartilage without injury to the latter. When pre- 

 pared in the cold, the toughness of the ligaments, 

 especially in the region of the vertebral column, 

 renders their removal a matter of great difficulty. 



1 These are the three commonest species cf the genus Raja brought 

 to the London market. For the distinguishing characters of the three 

 species see pp. 41 and 42, 54 and 60. Several of the figures are 

 taken from the common New Zealand species, R. nasuta. 



