PAEENTAL CARE AMONG FRESH-WATER FISHES. 455 



swim ill large shoals over the head of the mother. In case of danger, 

 the mother opens her mouth, and the fry find a safe retreat in the 

 thorax." 



If this statement could be relied on, viviparity would be proved, 

 but it is at least possible that the observers, seeing the eggs out, as- 

 sumed that what had really come from the mouth had issued from 

 the abdomen." Anyway, fry that had found their way from the 

 mouth into " the thorax " would not find it " a safe retreat." The 

 species has not been described or illustrated in such a manner as to 

 be intelligible. Mr. C. Tate Regan, of the British Museum {in litt.)^ 

 thinks that " the lau-lau seems to be an Arius;''^ possibly it is the 

 Netwna harhus. Another possibility is that it is related to or the 

 same as the gigantic pira'iba of the Amazons {Pirating a -fUavnentosa). 

 One objection to the last suggestion is that the flesh of the lau-lau 

 is said to be " delicious, both in the fresh state and when dried ; " in 

 fact, the " flesh is so much esteemed, that it is considered to be one 

 of the ties which binds him wdio has once tasted it forever to the 

 region where it is indigenous." On the other hand, the flesh of the 

 jjiraiba, is indigestible and even dangerous; in the words of its 

 monographer, E. Goldi (1901, 183), "a carne do Piraib'i e tida por 

 pesada, indigesta, perigosa mesmo com a continuagao." As British 

 Guiana belongs to a nation endowed with scientific investigators, we 

 may hope soon to know what the lau-lau really is. 



The Plotosids, or catfishes, of southern Australia have been also 

 claimed to be viviparous and they at least make provision for the 

 care of their young. In the report of the Royal Commission to ex- 

 amine into the fisheries of New South Wales, it is asserted that in " the 

 fresh-water catfish " {Copidoglanis tandanus) , " as in most if not all 

 of the Silurula', the ova are fertilized by the male fish before leaving 

 the body of the female, and both sexes seem to unite in the subsequent 

 attendance on the nest in which the ova are deposited." The intro- 

 mission of the semen among Silurids will be new* to ichthyologists 

 and physiologists. 



In fine, while it may be improbable that there is viviparity in 

 Silurids, it is not impossible, and these popular beliefs should l<5ad 

 to a candid investigation of the subject. 



SILURINES, ICTALURIXES, PIMELODINES, AND TACHISURINES 



All the fishes now referred to are related to such a degree as to 

 form a group called the family of Silurids by naturalists. It is the 

 largest and most comprehensive family of the order of Nematognaths, 



o In another place (I, p. 114) Schomburgk merely alludes to the " yoiing off- 

 s])riii.s;. which swan hi shoiils nhout [the parents], and in case of daiiKci' enter 

 the large throat of the mother." 



