490 PAKENTAL CARE AMONG FRESH-WATER FISHES. 



be barren on the surface may harbor a few inches below quite a 

 harvest in the shape of fishes which have found their way there for 

 refuge from the drought. It is this group of Ophiocephalids, too, 

 which furnishes some interesting examples of paternal care. 



The Ophiocephalids are elongated fishes with a flattish, declivous 

 head, scales of moderate size on the body and larger ones on the head 

 m oblique rows, a long dorsal and a long but shorter anal (both spine- 

 less) , and ventral fins behind or under the bases of the pectoral with 

 six soft rays, the outermost being undivided, but articulated distally. 

 These characters are supplemented by a peculiar modification of the 

 branchial apparatus adaptive to aerial respiration, as well as by many 

 ether anatomical characters. The labyrinthiform apparatus is also 

 useful under certain other disturbing conditions, according to Day. 

 " Wlien pollution or poisonous substances find access to rivers or mud 

 is carried down in such quantities as to choke the gills of most forms, 

 these Ophiocephalida? are almost- unaffected, for breath- 

 ing atmospheric air direct, the presence or absence of flu- 

 viatile contamination is not of such material consequence 

 to their existence. They are able to live until the poison 

 has passed downstream and the waters are again puri- 

 fied." The differences from all other fishes, indeed, are 

 so great that there is not universal agreement as to the 

 affinities of the family. 



The Ophiocephalids are about 30 in number and found 



in almost all the tropical and even subtropical regions of 



Fig. K.-ophio- tlie Old World, 3 occurring in Africa, but all the others 



cephaius. .^^ Southern and eastern Asia and the islands to the 



southward. In the Philippine Islands are found at least 5 species. 



There is no general English name that can take the place of Ophio- 

 cephalids. Snakeheads is a book name that interprets the Latin title, 

 but is rarely used. The word in most popular use is nnirrul, vari- 

 ously spelled, which is the common vernacular Indian term for species 

 of the family. 



When a prolonged drought dries up the ponds or bodies of water 

 in which they have flourished the snakeheads do not necessarily 

 succumb to the consequences, but are provided with means to contend 

 ttgainst the adverse conditions. Some burrow into the drying bot- 

 tom, sometimes to the depth of 3 or 4 feet even, into a moister horizon, 

 and in such places may survive till later rains release them from their 

 entombment and restore the waters to their former beds. The fishes 

 retain moisture enough to keep their gills from dessication and are 

 able to breathe the little air needed direct or even to suspend respira- 

 tion. Others wander from the receding pond to seek more favorable 

 cjuarters. Such emigrations are mostly engaged in during night time 



