30 NORTHERN ZOOLOGY. 



hands. The females deposit their roes in holes in the sand, where the males fecun- 

 date them, and it would appear that the parents look after their offspring, as they 

 are often dug up in the same pits with their little ones. 



We shall conclude our notices of the Peecoide^e with some general observa- 

 tions on their geographical distribution. Previous to the appearance of the 

 Histoire des Poissons such an attempt would have been entirely futile, and even 

 that splendid memorial of Cuvier's transcendent genius, a model for works on 

 Natural History, does not afford all the data we require, but is to be considered as 

 merely a frame-work to be filled up by future observers. It contains five hundred 

 species of this family, three hundred and twenty-seven of which, or about two- 

 thirds of the whole, are inhabitants of the Indian Ocean and warmer latitudes of 

 the Pacific : forty-nine frequent the eastern side of the Atlantic (including the 

 Mediterranean) , and one hundred and eighteen have been detected on the American 

 side of that sea, the greater part of them within the tropics. Few of the Per- 

 coidese attain high latitudes. Perca vulgaris, one of the most northern, exists in 

 the Siberian rivers which fall into the Icy Sea ; Lucio-perca sandra, Acerina 

 vulgaris, and Trachinus draco, are found as high as Sweden ; and Labrax lupus* 

 reaches the Danish coast. In the New World the Lucio-perca Americana (or 

 rather the Okow, if it be a distinct species) is the only one that has a range north- 

 ward at all approaching to these f, for in America the true perches are not so 

 arctic as the Sandre, though in Europe they are more so. Eight other percoid 

 fish, described in the preceding pages of this Fauna, inhabit the St. Lawrence, 

 or the Great Lakes from which that river issues, but none of them go to the north 

 of the fiftieth parallel, while the Okow extends to the fifty-eighth. One species of 

 perca is found in Patagonia, and Trichodon Stelleri inhabits the sea of Kamt- 

 schatka, stretching over to Russian America. 



Before speaking more particularly of the distribution of forms, or the range of 

 species, it is advisable that we should enumerate the fresh-water genera, though 

 the line of division betwixt them and the oceanic ones cannot be drawn with pre>- 

 cision, because some genera, composed mostly of fresh-water species, contain one 

 or two which exclusively inhabit the ocean J ; or, on the contrary, a marine genus 



* In page 1 the southern shores of Britain are assigned as the northern limit of the range of this species, on the autho- 

 rity of the Hist, des Poissons; but Professor Reinhardt enumerates it among the Danish fishes, in a paper recently read 

 before the Natural History Society of Copenhagen. 



t The Okow does not, however, exist in the rivers that flow into the Polar Sea. 



| All the East-Indian Dules inhabit the fresh waters, but the two American species are found in the Caribbean sea. 



