RAYS. 319 



classes, both fresh and salted ; the females and 

 young are called Maids, and are considered best 

 for the table. The flesh is in best condition in 

 autumn and winter ; becoming soft and woolly 

 in spring and summer, which is the spawning 

 season. Great numbers are caught, however, at 

 these times, their approach to the shore render- 

 ing their capture more easy. 



The acute spines with which so many of the 

 Rays are studded, make them dangerous to 

 handle ; no doubt they may be considered as 

 weapons of defence, if not of offence. It is 

 observable that the long and flexible tail is 

 always the most effectively armed : we have 

 already seen how the spine of the Trygon is 

 used ; the learned zoologist to whom we are 

 indebted for that information, has also described 

 the defensive action of the Skate. " The point 

 of the nose and the base of the tail are bent 

 upwards towards each other : the upper surface 

 of the body being then concave, the tail is lashed 

 about in all directions over it, and the rows of 

 sharp spines frequently inflict severe wounds." 



Family IV. Petromyzonid^. 



(Stone- suckers.) 



We have now arrived at the lowest examples 

 of organization among Fishes, and consequently 

 the bottom of the scale formed by the series of 

 animals having an internal skeleton of bone and 

 a vertebrated spine. Throughout the whole of 

 this Order we have seen how the former charac- 

 ter has become less and less distinct, the skeleton 



