GEOGRAPHICAL DISTRIBUTION OF THE GADID^. 545 



eru varieties of the Gadidw very suddenly occur in great numbers, not 

 so much as regards individuals and species, but as regards genera, and 

 these partly live at a great depth, which the Gadidw do not do other- 

 wise. This shows that the water is not very briny, that its temperature 

 is moderate, and that there is great abundance and variety of food. 

 According to Lowe's account (184G), only Macrurus atlanticiis occurs 

 near Miideira; this fish does not even belong to the Gadidcc, while Dr. 

 Giiuther, in 18G8, found in the same waters no less than 10 genera and 

 12 species of Gadidcc. 



The ]\Iediterranean contains a considerable number of Gadidw even in 

 proportion to its fish fauna, which is peculiarly rich in genera and spe- 

 cies. As regards the genera, they are about evenly divided betweea 

 northern and southern varieties, while in the species there is a very 

 striking preponderance of northern varieties. This is only another 

 proof of the law of nature, that the torrid zone is rich in genera, the 

 temperate zone in species, and the frigid zone in individuals. Accord- 

 ing to Eisso, we find in the Mediterranean C genera with 11 species, and 

 according to Dr. Giiuther (1868), 10 genera with 19 species. There is 

 a remarkable diiierence between the western and eastern parts of the 

 Mediterranean. The western part extends from the Strait of Gibraltar 

 as far as the Strait of Messina ; in the eastern part we include the Black 

 Sea. Strinsia tinea is a variety of the Gadidw peculiar to the Mediter- 

 ranean. By the predominance of the genus Gadus the Mediterranean 

 has a northern character, Avhich, however, is strongly varied by a strong 

 addition of South Madeira varieties. As there are near the North Ca- 

 nary Islands, and in the western part of the Mediterranean, 10 genera 

 of Gadidw out of a total number of 22 — more than 45 per cent. — we find 

 here the greatest number of genera. 



In the Black Sea there are only 2 genera with 2 species, viz, Gadus 

 euxinus and Lota vulgaris. Four genera with five species, among these 

 two deep-water fish, are peculiar to the l>forth Canary Islands and Ma- 

 deira. Kear the South Canary Islands, which are 40-50 geographical 

 miles farther south, we find only Mora mediterranea. The Atlantic 

 region is thus indicated by a distinct border-line. The temperature of 

 the water is +6 to -f 8 degrees, Celsius. 



As a scattered northern variety we find, strange to say. Lota vulgaris 

 near Pine Island on the southwest point of Florida.* The occurrence of 

 this genus in the lagoons of West Key can only be explained by sup- 

 posing that Lota vulgaris belonged to the Mississippi, went into the sea 

 to escape the great heat in the river, and was then driven by the hot 

 Gulf Stream into the fresh-water stream near the coast. As a scattered 

 southern variety, we find in the south temperate zone of the Atlantic 

 Ocean, via the mouth of the La Plata lliver, near Montevideo, Phycis 

 hrasiliensis, which is, of course, peculiar to those waters. 



* Loia maculosa, which is the species referred to, has uot been recorded from farther 

 south than Kansas City, Missouri. Pine Island Lake, in the Hudson's Bay region, is, 

 perhaps, the locality intended. — B. 

 35 F 



