18 



SCIENCE. 



[N. S. Vol. XXII. No. 549. 



perhaps, the same mechanical basis as Helm.- 

 holtz's explanation, it seems not amiss to ap- 

 proach it in this way. An attempt is being 

 made at a mathematical treatment. 



C. C. Trowbridge, 



Secretary. 



DISCUSSION AND CORRESPONDENCE. 

 HIGHER AND LOWER. 



To THE Editor of Science : In the American 

 Naturalist for June, on page 413, L. J. C. 

 takes exception to the custom of referring to 

 animals as ' higher ' and ' lower,' on the ground 

 that these terms tend to give the student an 

 idea that the vertebrate affinities lie in a direct 

 chain, rather than forming a complicated, 

 branching system. 



This criticism will strike some as a little 

 captious since the terms do not imply a direct 

 connection, but merely that some animals are 

 on a higher plane than others, just as the 

 dwellers on the fifth floor of an apartment 

 house are higher than those on the fourth 

 floor. The terms generalized and specialized 

 fail to convey the idea intended because a 

 highly specialized animal may be low in the 

 scale of life. The sloth is more specialized 

 than the monkey, but it would naturally be 

 termed a lower animal; thus though what we 

 call the ' higher ' animals are, as a rule, more 

 specialized than the ' lower ' forms, they are by 

 no means invariably so. To revert to the 

 apartment house it may be said that a family 

 on the fifth floor might be related to one on 

 the fourth and another on the sixth and yet, 

 as a whole, the fifth floor people would be 

 higher than those below. 



F. A. L. 



A DENIAL. 



To THE Editor of Science : In a circular 

 sent out by The Macmillan Company ad- 

 vertising one of their recent publications, the 

 assertion is gratuitously made that I ' uphold 

 Wallace's position.' Kindly allow me the 

 space to deny the statement and to explain 

 that it' arose first from a misapprehension, 

 which was later compounded by a clerical 

 error — not mine. 



Hubert Lyman Clark. 



SPECIAL ARTICLES. 

 THE FISHES OF PANAMA. 



In the Zoological Club of Indiana Uni- 

 versity in 1885 or 1886 President D. S. Jordan 

 gave a resume of the facts known at that time 

 concerning the relation of the marine faunas 

 on the two sides of Panama. It was jokingly 

 remarked at that time that at the rate of 

 progress the canal might be finished by 1900 

 and that zoologists would have to bestir them- 

 selves to record the faunas as they exist before 

 the Panama canal would mix things up. It 

 is now 1905 and the canal is not finished. In 

 the meantime the marine faunas have been 

 dealt with by 



1. Gregory, L. W. : ' Contributions to the 

 Palseontology and Physical Geology of the West 

 Indies,' Quart. Journ. Geol. Soc, Vol. 4, 1895, 

 pp. 255-312. 



2. Faxon, Walter : ' The Stalk-eyed Crustacea,' 

 Mem. Mus. Comp. Zool'., Harvard College, Vol. 

 XVIII., 1895, pp. 1-292. 



3. Gilbert, C. H., and Starks, Edwin C. : ' The 

 Fishes of Panama Bay,' Mem. Cal. Acad. Sci., Vol. 

 IV., pp. 1-226. 



Gilbert and Stark's conclusions are that: 

 " The ichthyological evidence is overwhelm- 

 ingly in favor of the existence of a former 

 open communication between the two oceans, 

 which must have been closed at a period suf- 

 ficiently remote from the present to have per- 

 mitted the ' specific differentiation of a very 

 large majority of the forms involved." They 

 found that ' of the 83 families of fishes repre- 

 sented at Panama all but 3 (Cerdalidse, Cir- 

 hitidse and Nemat^stiidse) occur also on the ! 

 Atlantic side of Central America; while of 

 the 218 genera of our Panama list, no fewer 

 than 170, are conunon to both oceans.' Eifty- 

 four out of a total of 374, or 144 per cent., of 

 the Pacific coast species are identical with 

 Atlantic coast species. 



I have just finished a consideration of the 

 geographical distribution of the freshwater 

 fishes of tropical America and Patagonia as 

 applied to the Archihelenis-Archiplata theory 

 of von Ihering. The details will appear in 

 one of the volumes of the Hatcher reports of 

 Princeton University. The evidence there 

 collected indicates that the Pacific slope fauna 



