OCTOBEE 11, 1901.] 



SCIENCE. 



551 



K. Hawaii and the East Indies. 



Genera* chiefly confined to Hawaii 4 



Genera of wide distribution in the equa- 

 torial Pacific 123 



Generaf confined to Hawaii and the West 

 Indies 1 



Summary. 

 Genera (shore fishes only) in the Mediter- 

 ranean Sea 144 



Genera in the Red Sea 191 



Genera in India 280 



Genera in Japan (exclusive of northern 



forms) 334 



Genera in Australia 344 



Genera in New Zealand 108 



Genera in Hawaii 144 



Genera about Panama 256 



Genera in West Indies 299 



EXTENSION OF INDIAN FAUNA. 



From the above tables it is evident 

 that the warm- water fauna of Japan, as 

 well as that of Hawaii, is derived from the 

 great body of the fauna of the East Indies 

 and Hindostan ; that the fauna of the Red 

 Sea is derived in the same way ; that the 

 fauna of the Mediterranean bears no especial 

 resemblance to that of Japan, rather than 

 to other elements of the East Asiatic fauna 

 in similar conditions of temperature, and 

 no greater than is borne by either to the 

 West Indies ; that the faunas of the sides 

 of the Isthmus of Suez have relatively little 

 in common, while those of the two sides of 

 the Isthmus of Panama show large identity 

 of genera, although few species are common 

 to the two sides. Of the 255 genera re- 

 corded from the Panama region, 179, or over 

 70 per cent., are also in the West Indies ; 

 while 68, or more than 30 per cent, of the 

 number, are limited to the two regions in 

 question. 



THE ISTHMUS OF SUEZ AS A BARRIER 

 TO DISTRIBUTION. 



With the aid of the above table, we may 

 examine further the relation of the fauna 



" Holotrachys, Cirrhitops, Perkinsia. 

 t Malacanthus. 



of Japan to that of the Mediterranean. If a 

 continuity of shore-line once existed, it 

 would involve the obliteration of the Isth- 

 mus. With free connection across this isth- 

 mus, the fauna of the Red Sea must have 

 been once practically the same as that of the 

 Mediterranean. The present differences 

 must be due to later immigrations to one 

 or the other region, or to the extinction of 

 species in one locality or the other, through 

 some kind of unfitness. In neither region 

 is there evidence of extensive immigration 

 from the outside. The present conditions 

 of water and temperature differ a little, 

 but not enough to explain the difference in 

 faunte. The Red Sea is frankly tropical 

 and its fauna is essentially Indian, much 

 the same, so far as genera are concerned, 

 as that of Southern Japan. The Mediter- 

 ranean is at most not more than semi- 

 tropical and its fishes are characteristically 

 European. Its tropical forms belong 

 rather to Guinea than to the East Indies. 

 With the Red Sea the Mediterranean has 

 very little in common, not so much, for ex- 

 ample, as has Hawaii. Forty genera of 

 shore fishes (and only fifty of all fishes) 

 are identical in the two regions, the Medi- 

 terranean and the Red Sea. Of those, 

 every one is a genus of wide distribution, 

 found in nearly all warm seas. Of shore 

 fishes, only one genus in seven is common 

 to the two regions. Apparently, there- 

 fore, we cannot assume a passage across 

 the Isthmus of Suez within the lifetime of 

 the present genera. Not one of the types 

 alleged to be peculiar to Japan and the 

 Mediterranean is thus far known in the 

 Red Sea. Not one of the characteristic- 

 ally abundant Mediterranean types * crosses 

 the Isthmus of Suez, and the distinctive 

 Red Sea and Indian types f are equallj^ 



* As Crenilahrus, Labrus, Symphodus, Pagellus, 

 Spondyliosoma, Sparisoma. 



t As Chxlodon, Lethrinus, Sphcerodon, Abudefduf, 

 etc. 



