PAKENTAL CARE AMONG FRESH-WATER FISHES. 



451 



con form at ion of the ventral fins, those of the females appeared to be 

 larger than those of the males ; "" further, " these rays were thick- 

 ened by a deposit of fat. while the innermost one had a large pad 

 attached to its posterior edge." He therefore assumed that '" these 

 fins can be expanded into a cuplike surface, the use of which may be 

 to receive the eggs as extruded, which may be vivified there by the 

 male." 



As soon as the eggs are extruded by the female and fertilized, they 

 are taken by a male, but whether from the ventral pouch improvised 

 by the female or from the open Avater is unknown. In the mouth 

 the,y are probably retained until they are hatched and the fry pre- 

 pared to take care of themselves. The interior of the mouth is 

 capacious and the oral cavity separated from the stomach by the 

 esophagus, which exercises the function of a sphincter and confines 

 the eggs and fry to the cavity. AVyman, however, found " in one 

 instance, besides some nearly mature foetuses contained in the mouth, 

 two or three were squeezed apparently from the stomach, but not 

 bearing any marks of 

 violence or of the ac- 

 tion of the gastric 

 juice." Wyman nat- 

 urally assumed that 

 " it is probable that 

 these found their way 

 into that last cavity 

 after death in conse- 

 quence of the relaxa- 

 tion of the sphincter, which separates the cavities of the mouth and 

 the stomach." 



The number of eggs carried by the males varies between eight or 

 ten and forty or fifty. W^aiian found between twentv and thirty. 

 " The mouth and branchial cavity Avere very much distended, round- 

 ing out and distorting the Avhole hyoid and branchiostegal region. 

 Some of the eggs even partially protruded from the mouth " in one 

 of Wyman's fishes. But, with the exception just noted, '' no young 

 or eggs were found in the stomach, although the mouth was crammed 

 to its fullest capacity." 



The length of time during which the eggs are retained within the 

 mouth is unknown, but it must be considerable. Before the period 

 of oviposition both males and females in India " are said to be so 

 fat that the curry made with them resembles that made with pork; 

 but after swimming about for a few days with their mouths full of 

 eggs," the males become, according to Boake. "dry and insij:>id." 

 Eventually they may become quite emaciated. Boake thought that 

 the ovigerous stage lasted for " a period of some weeks." Perhaps 



Fig. 33. — A nearly mature foetus of natural size of a sea catfish 

 or Taphisurine. After Wvman. 



