NA TURE 



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THURSDAY, JUNE iS, 190S. 



IHE FRESH-WATER FISHES OF CENTRAL 

 AMERICA. 



Biologia Ccnirali-Aincricana. Pixccs. By C. Tate 

 Regan. Pp. xxxiii + 2u3; with 26 plates and 2 maps. 

 (1906-S.) 



WE have to congratulate the editor of this magni- 

 ficent work on the regularitj- with which the 

 issue of the parts, now 200 in number, is proceeding, 

 thus bringing its completion within measurable dis- 

 tance. Many a time, when, during its progress, col- 

 lection after collection arrived, each bringing insects 

 in tens of thousands, besides specimens of almost 

 every other class oT animals, the prospect of com- 

 pleting the^'ork must have appeared almost hopeless, 

 and this still more so when the editorial labours were 

 thrown entirely upon Mr. Godman after the death 

 of his coadjutor, Osbert Salvin. When the founders 

 of the " Biologia " planned the work, now some forty 

 vears ago, they were moved to this grand enterprise 

 bv a clear perception of the important bearing which 

 an intimate knowledge of the fauna of Central 

 America, as a transition area between the Nearctic 

 ;uid Neotropical regions, must have upon the wider 

 questions of the changing distribution of animals 

 generally, and of their evolution since Tertiary times. 

 But we believe that their original estimate, both of 

 the number of species and of the extent of the work, 

 was greatly exceeded in the course of those years. 

 Nevertheless, their determination and energy have 

 never failed them. 



The volume with which we propose to deal on the 

 present occasion is that containing an account of the 

 fishes. Its appearance marks also the completion of 

 the whole division of vertebrates. The preparation 

 was entrusted to Mr. C. Tate Regan, who by his 

 previous work on Neotropical fishes had shown him- 

 self eminently qualified for the task. The editor was 

 most fortunate in his selection, for in the short space 

 of two years he saw a work completed which was not 

 only difficult in itself, but was rendered more laborious 

 bv the numerous contributions to Central American 

 ichthyology which have appeared during the last two 

 decades, and which, of course, had to be carefully con- 

 sulted and studied. 



The author has restricted himself almost entirely to 

 fresh-water fishes and to such marine forms as are 

 known to ascend rivers beyond the influence of the 

 tide. In accordance with the plan generally followed 

 in the " Biologia," detailed descriptions, with full 

 references to previous publications, are given in the 

 case of groups or species which to the author appeared 

 to need revision, and for which the requisite materials 

 were to be found in the British Museum. The re- 

 mainder are merely mentioned by name, with the 

 addition of such distinctive characters as may be com- 

 pressed in a synopsis or key. 



We find, then, that the number of species described 

 is 330, including some truly marine forms which for 



NO. 2016, VOL. 78] 



comparison, or other reasons, had to be referred to. 

 This is a surprisingly small number considering that 

 about 700 reptiles and 200 batrachians are known from 

 the same area — an area which has been peopled from 

 two regions, the Nearctic and the Neotropical, and 

 also by migrations from two oceans; offering every 

 variation of physical condition most favourable to the 

 development of fish-life; intersected by networks of 

 river systems, without intercommunication ; and with 

 large expanses of water severally containing numer- 

 ous representatives of the same genus. An area such 

 as this must nourish a multitude of specific forms, of 

 which only a fraction are as yet known to us. We 

 can therefore fully concur with the author when he 

 says that our knowledge of the fishes of Central 

 America and Mexico must still be regarded as very 

 incomplete. He directs attention to the fact that not a 

 single fresh-water fish has as yet been described from 

 Honduras or from Nicaragua north and east of the 

 Great Lakes. He mi,ght have added that fishes, for 

 obvious reasons, are not favourites with the generality 

 of collectors. Extensive collections are only made by 

 those who are especially interested in the subject; and 

 we believe that since Salvin, assisted by Capt. Dow 

 and Mr. Godman, formed his collection, no other of 

 equal extent has been made, unless it be that of 

 Mexican fishes, brought together by Dr. Meek. We 

 must not omit to mention here that the acquisition 

 by the British Museum of numerous types or co-types 

 fiom various, especially .American, sources is chiefly 

 due to the efforts of Mr. Regan himself. 



The systematic work has been carried out in every 

 detail with painstaking care and accuracy. Generally 

 we notice with pleasure that in nomenclature he has 

 kept free from the crotchets of modern reformers, and 

 has remained faithful to the classical spirit which one 

 expects to find in a Cambridge graduate. With the 

 rich materials at his disposal, and the additional in- 

 formation contained in the writings of his contem- 

 poraries, he has aimed at a precise definition of genera 

 and species, by which their identification has been 

 much more facilitated than if he had prepared those 

 lengthv descriptions which too frequently prove a snare 

 for the student. 



We cannot enter more fully into the treatment of 

 the subject in the systematic section of the work, in- 

 volving in the case of almost every species questions 

 of a purely technical nature. But there is one point 

 which may be mentioned, if only as a suggestion to 

 other authors engaging in similar work. Students 

 would find it a great boon if direct references 

 to good illustrations were always admitted in the 

 " svnonymy," instead of references merely to some 

 recent publication, in which they learn for the first 

 time that such illustrations exist. Furthermore, in 

 the case of the "Biologia," it would have been par- 

 ticularly appropriate to give direct references to figures 

 of species discovered by Salvin, and drawn from speci- 

 mens collected bv him. We allude, inter alia, to the 

 genus Heros and its allies, for which Mr. Regan has 

 adopted the Swainsonian name " Cichlasoma." ' 



1 Should be superseded, according to modern nomenclature, by the prior 

 Cichlaurus ! 



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