328 FISHES 



as a human fist, in other words it is about six inches in dia- 

 meter. Many of these nests were taken and examined during 

 the voyage of the French exploring vessel " Talisman " in 1883. 

 They have also been described by the American naturalist 

 Alexander Agassiz, who died recently after a long and dis- 

 tinguished career. Until lately the nests in question were 

 generally attributed by naturalists who had studied them to the 

 sargasso-fish, scientifically known as Pterophryne, a small fish 

 allied to the well-known angler or fishing frog of our own seas. 

 This fish belongs to a family most of whose members live among 

 coral-reefs, where they are concealed by their colour and the 

 appendages of the skin ; but Pterophryne makes use of the 

 peculiar arm-like pectoral fins which are characteristic of all the 

 angler tribe, to support itself on the floating sargasso. Recently, 

 however, an American naturalist Mr. Gudger, has had the 

 opportunity of observing the spawning of Pterophryne in the 

 aquarium of a Biological Laboratory in S. Carolina. Specimens 

 of the fish were living in a tank with pieces of sargasso weed, 

 and when they spawned they made no nest at all, and produced 

 eggs not provided with threads but held together in a sheet of 

 gelatinous material exactly like the spawn of the common angler. 

 The nests found in the sargasso must therefore be the work of 

 some other, at present unknown fish, and it is most probable 

 that this unknown parent is one of the flying fishes, since these 

 belong to the same family (Scorn bresocidae) as the gar-fish 

 {Be, one), the eggs (Plate XXVII., B) of which are known to be 

 provided with filaments arising in groups from opposite poles. 



The curious habit of carrying the eggs in the mouth during 

 their development occurs in two families of fishes widely 

 separated in classification, namely the cat-fishes (Siluridae) and 

 the Cichlidae, the former belonging to the primitive sub-order 

 of carp-like fishes (Ostariophysi) and the latter to the most 

 specialised group of Teleostei, namely the perch-like fishes of 

 the spiny-finned group. In their general appearance and 

 structure the Cichlidse, formerly called by Giinther Chromides, 

 resemble the wrasses of our own coasts, and as previously sug- 

 gested may be regarded almost as fresh- water wrasses. It is 

 difficult to account for the evolution of such a habit ; we can 

 only form conjectures concerning the modes in which it might 

 have arisen. If we assume that it was throughout due to 



