NATURAL SCIENCES OP PHILADELPHIA. 95 



forms thus brought together a strong likeness, but yet there are others which, 

 in almost all anatomical and zoological characters, show a greater affinity to 

 species that by those principles of classification would be referred to distinct 

 families. While the above mentioned families are therefore for the present 

 retained, it is with the understanding that such is done simply because our 

 knowledge of the true principles of classification is not sufficiently perfect, and 

 not because they are believed to be founded in nature. The typical Percoids, 

 Pristipomatoids, Sparoids and Primelepteroids, appear, for example, to be as 

 nearly allied to each as are ,the Rhyptici to the Percoids. They cannot be 

 distinguished by any character except the dentition ; and characters drawn 

 from that alone, important as it is in many cases, can scarcely of itself be 

 sufficient to establish family groups. It is probable that all of those fishes 

 will hereafter be united, and quite a different distribution of the genera be 

 adopted. 



Notes on the Habits of APHREDODERUS SAYANUS. 

 BY CHARLES C. ABBOTT. 



If we except the knowledge of this fish's existence, nothing seems to be 

 known concerning it; though few of our fluviatile species have a greater geo- 

 graphical distribution, or are more numerous in many extended and widely 

 separated localities. At Camden, New Jersey, this species abounds in immense 

 numbers ; during spring, in schools, similar in size and general appearance, to 

 the young of Amiurus De Kayi or atrarius; in summer and autumn remaining 

 in pairs generally, though often in companies of from five to nine ; in winter 

 scattered irregularly through the streams ; each seeking shelter, and generally 

 more than half burying themselves in the sand; though to clay or plastic mud 

 they seem to have a great aversion. 



The Aphredoderus is most strictly carnivorous, and appears to delight in the 

 unnecessary destruction of all malacopterygian fishes, not excepting its own 

 species, if they be too weak to withstand its attacks. Immature cyprinoidsare 

 its favorite food, though the Melanura annvlata is chiefly its victim. Being 

 strictly nocturnal in its habits, little opportunity is offered to learn its peculiar 

 mode of capturing its prey, but from the fact of often finding the tail of a 

 cyprinoid projecting from the jaws of the Aphredoderus, and from the position 

 in which the author has universally found the prey, when specimens were dis- 

 sected, there is little doubt that " head foremost^ is the usual fashion. The 

 dentition is not of such character as to lead to the idea of extreme carnal 

 propensities of the species in question ; and yet it may be doubted if any fluvia- 

 tile species is more so, if we except the Belone longirostris. The pikes we know 

 are strictly carnivorous, but there is no instance in our memory of that fish 

 destroying others for the mere sake of destruction. Three specimens living, a 

 few months since, in the aquarium of the Academy, were attentively watched 

 by the author, and in the space of eleven days they had destroyed twenty-seven 

 black-nosed dace, (Argyreus atronasus,) and by continued worrying succeeded 

 in the destruction of a mud sun-fish, (Ambloplites pomotis,*) nearly quad- 

 ruple their size. 



From the comparison of specimens from different localities, it is highly 

 probable that two species may be detected. The author has taken specimens 

 near Philadelphia, exactly coinciding with Gilliam's description, but varying 

 in the general lint of the body, and in the want of the white margin of the 

 caudal fin. On examining specimens from Cedar Swamp Creek, N. J., taken 

 by Prof. S. F. Baird, and the originals of his description, in his Report of the 



*This fish was first described by Baird, as Centrarchus pomotis ; but is congeneric with 

 Ambloplites rupestris Gill, and must be so referred. 

 Ambloplites pomotis Abb. 



Central chits pomotis Baird, Ninth Smith. Rep. p. 325. 



1861.] 



