PARENTAL CARE AMONG FRESH- WATER FISHES. 517 



{Geophagus lapidifera) Avas observed by Castelnau in the Araguay 

 River to carry many pebbles, one by one in its month, to a spot where 

 it deposited them to form a nest. These pebbles were the size of the 

 end of a finger. In this nest the eggs, resembling mustard seed, Avere 

 laid. 



Like the Centrarehids, the Cichlids, probably generally, exercise 

 a parental care, but according to some great authorities (Boulenger 

 and Pellegrin) in most cases the females assume guardianship. 

 Pellegrin found that all the individuals (four) of a common TiJapia 

 of Palestine {T. simonis) examined by him which had eggs in the 

 mouth Avere females. Boulenger confirmed the ovigerous agency of 

 the females for many other species. At present, in fact, it appears 

 that in most (probably all) of the African Cichlids, at least, the 

 females are the Qgg carriers rather than the males. 



The earliest information respecting the oral gestation of the Bra- 

 zilian si^ecies was given by Agassiz (220) from observations on " a 

 >j)ecies of Geophagus'''' (the sex not stated). "The eggs pass,'' he 

 knew not how, " into the mouth, the bottom of Avhich is lined by them, 

 betAveen the inner appendages of the branchial arches, and espe- 

 cially into a pouch formed bv the upper pharyngeals, AA'hich they 

 completely fill. There they are hatched, and the little ones, freed 

 from the egg case, are developed until they are in a condition to 

 provide for their OAvn existence." He did " not knoAv Iioav long this 

 (continues," but had '"■ met Avith specimens Avhose young had no longer 

 any vitelline sac. but Avere still harbored by the progenitor." Occa- 

 sionally, instead of eggs, Agassiz " found the cavity of the gills, as 

 also the space inclosed by the branchiostegal membrane, filled Avith 

 a brood of young already hatched. The eggs before hatching are 

 ahvays found in the same part of the mouth, namely, in the upper 

 i)art of the branchial arches, protected or held together by a special 

 lobe or valve formed of the upper pharyngeals." The cavity thus 

 occupied by the eggs Avas thought l)y Agassiz to correspond " exactly 

 to the labyrinth " of the fishes Avith labyrinthiform pharyngeals. 



AN OI.IJ EGYP'J'IAN AND PALESTINIAN OVIGEROUS flCIILIU. 



The principal and longest knoAvn of the Cichloid genera is Tilapia, 

 for a long time generally called Chromis. One species, indeed, Avas 

 familiar to a numerous and highly civilized population thousands 

 of years before there Avas an English language. It Avas the object 

 of the angler's as Avell as professional fisherman's pursuit along 

 the banks of the Nile under the Pharaohs, and was sculptured on 

 various monuments. The same species and closely related ones are 

 inhabitants of I'alestine and undoubtedly Avere the chief i)roducts 



