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 rendering 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. Petromyzonidæ.
(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 character has become less and less distinct, the skeleton
