458 PARENTAL CARE AMONG FRESH-WATER FISHES. 



Long ago Hancock described the movement of the flatheaded has- 

 sar of Demerara (Dortis hanrockU) . A friend informed him that on 

 one occasion he and his family " fell in with a drove of these animals, 

 which Avere on their march over land to a branch of the Pomeroon. 

 They were so nnmerons that the negroes filled several baskets with 

 those they picked np."' Their movements '' over land " have been 

 compared to those of '' the two-footed lizard. They project them- 

 selves forward on their long arms (the stont pectoral spines) by the 

 elastic spring of the tail exerted sideways. Their progress is nearly 

 as fast as a man will leisurely walk. The strong scuta or bands 

 which envelop their body must greatly facilitate their march,"' Han- 

 cock thought, " in the manner of the plates under the belly of ser- 

 pents, which are raised and depressed by a voluntary power, in some 

 measure performing the office of feet."' 



Under ordinary conditions, the fiathead, according to Hancock, 

 " frequents only the fresh water of pools, lakes, and rivers, lives by 

 suction, and on aquatic insects, and grows to about a foot in length." 



No details of the courtship and parental care of any Doradine have 

 been published. All that is known is wdiat Hancock (1828) has told. 

 " Both " of the species of Xematognaths which he noticed as " species 

 of hassar " — the Doras and Tloplosternnm — "make a regular nest; " 

 the nest of the Doras is made " of leaves " while that of the Hoplo- 

 sternimi is made " of grass; " the eggs are laid " in a flattened cluster,"' 

 and covered " over most carefully." Like the roundhead, the flat- 

 heads " lay their eggs only in wet weather." Afterwards the parents 

 are said to " remain by the side of the nest till the spawn is hatched."' 

 It has been especially asserted that " both the male and female " share 

 ,in guarding the nest, " steadily hatching the spawn and courageously 

 attacking any assailant." 



THE RAAD OR ELECTRIC CATFISH. 



Almost all the meml)ers of the Nematognath order have stout dor- 

 sal and pectoral spines, but the electrical catfish, like other electrical 

 fishes, is entirely deprived of spines or dermal armature of any kind ; 

 its electrical battery replaces all such protective devices and is more 

 than a compensatory substitute. The family Malapterurida^ " has 

 been proposed for it. The body and head are entirely naked and 

 unarmed, the mouth is terminal, the barbels are like those of the 

 typical catfishes, a true dorsal fin is wanting but there is a large adi- 

 pose on the back of the tail far behind, the pectorals are lateral and 

 unarmed, and the ventrals submedian. 



The proper name of Malapteruricljo is Torpedinidfe. (See Proc. U. S. Nat. 

 Mus., XXVI, l!)Uo, ()07. (')!»S. 



