84 Cincinnati Society of Natural History. 



These horny cases, in the Port Jackson sharks of the Pacific, are 

 twisted into a spiral form. 



In some of the flying fishes the eggs are entirely covered with 

 delicate filaments which entwine with each other, and they are 

 thus held together in considerable masses; and in a similar manner 

 the eggs of the gudgeon (^Menidia notata), of the Chesapeake Bay, 

 are held together, there being four long and slender threads 

 attached to one side of each egg. 



You are all familiar with the polygamous, four-spined stickle- 

 back, the male of which species builds a cunning, basket-like nest 

 between the upright stems of water plants, in which he induces his 

 several wives to deposit their eggs, and which he watches and cares 

 for until hatched. Some of the fishes of the gulf stream — notably, 

 the Antennarius — build a kind of nest among the floating seaweed; 

 also the snakehead fish (Ophiocephalus), of India, and a small cat- 

 fish (^Callic/it/iys), of South America, construct nests of bits of 

 waterweeds, in which the ova is deposited and carefully tended 

 by the male. 



Among the fishes which carry the ova in various portions of 

 the body until hatched may be mentiontd the marine catfish 

 (^Galeichthys felis) of our Southern coasts. The female deposits, 

 in a slight depression in the sand, ten or twenty yellowish-white 

 eggs as large as Malaga grapes, which are fecundated by the male 

 and then taken into his mouth and placed between the leaves of 

 his gills, where he retains them until the young are hatched and 

 able to take care of themselves. At this time his pharynx is 

 enormously distended and presents a very curious and comical 

 appearance. 



Agassiz, during his journey up the Amazon, discovered a species 

 that incubated its eggs in the mouth, and Dr. Lortet gives some 

 very interesting observations on the similar propagation of a species 

 (^Tilapia simonis), belonging to Lake Tiberius, in Palestine. The 

 female deposits about two hundred eggs in a shallow excavation, 

 whi.-h are first fecundated by the male and then taken, one after 

 another, into his mouth, where they are retained in the buccal 

 cavity, distending the checks in an extraordinary manner. The 

 eggs hatch in several days, and the young fishes are pressed one 

 against the other like the grains of a ripe pomegranate. The 

 mouth of the father becomes so distended that his jaws can not 

 meet, and he presents a very strange appearance. Some of the 

 young continue to live and develop among the folds of the gills; 



