FOURTEENTH ANNUAL MEETING. 6l 



a contrivance which is peculiarly adapted for protecting the 

 eggs against the violent motions made by the male who aerates, 

 attends and incubates the eggs. In these eggs there is an inner 

 true egg membrane, and an exterior mucous adhesive layer, 

 separated from the inner one by elastic pillars, placed at inter- 

 vals, so that the resulting arrangement is an extremely elastic 

 one, and yields readily to the motions made by the male with 

 his fins. In this case the eggs adhere together in masses very 

 much the same way as in the eggs of the frogs. 



There is 3'et another singular contrivance, which was first de- 

 scribed by Professor Jeffries Wyman, of Boston. This is 

 found in a species of the armored catfish of South America. 

 In this case [Aspredo) the male fish is provided with a numerous 

 series of little stalks, formed on the under surface of the ab- 

 domen, and the cup-like extremities of the stalks into which the 

 eggs are received are supplied with capillary vessels, an arrange- 

 ment being thus developed which constitutes not only a sup- 

 porting stalk, but also a kind of placenta. It is said — although I 

 am not sure that the evidence is very trustworthy — that one 

 species of the gar lays its eggs in strings in a single row, like 

 the common toad. There are other cases in which the ova are 

 uncovered and directly adherent to the abdomen or under side 

 of the tail, as in the case of some of the pipe fishes of Europe. 

 In some of our American species of pipe fishes the eggs adhere 

 beneath the tail in a couple of rows, but are covered by expanded 

 folds of the skin. There are other cases in which the eggs are 

 carried into a pouch formed by the ventral fins. In other species 

 there exists an abdominal or rather caudal pouch which opens 

 just behind the vent of the male, and into which the eggs are 

 received and incubated. In one instance a fish of this class 

 {Hippocampus) hatched out under my observation about 150 ova ; 

 the drove of embryo sea horses which were finally set free in 

 the aquarium, were an interesting study. 



Then the number of species which suspend their eggs is quite 

 considerable. The black, leathery case of the common ovipa- 

 rous ray has four filamentous horns, one at each corner, which 

 wind around plants and suspend the eggs to weeds, so that as 

 the tide sweeps by these horns, which have openings in them, 



