42 SUPPLEMENT ON 



also with the summer season the species of mugil, thynnus, 

 and exocetus, pass up the Mediterranean, and return in 

 autumn, at the same time that deep water percoid, sparoid, 

 serrani, lampris, &c. aided by that portion of current which 

 ascends northward off the coast of Spain, and sweeps round 

 the Bay of Biscay, range along the soundings, not unfre- 

 quently as far as the islands in the British Channel. Some 

 of the same species are found during the opposite season 

 penetrating south to beyond the Cape of Good Hope, where 

 they are turned back by the south-east monsoon, and the 

 receding sun. On the east coast of South America the same 

 species occur, no doubt brought by similar means from the 

 west of Africa ; but here the general direction of the land 

 being to the westward of south, the southern part of the 

 tropical current continues along the coast to a much higher 

 latitude, before the effect of the south-westem winds operate 

 fully upon it ; hence the tropical species of fish, at least dur- 

 ing the antarctic summer, spread further south, and possibly 

 are not completely repelled until the cold and storms about 

 the Falkland and Magellanic Straits effect that purpose, in 

 latitudes where the gadoid species of the south come to meet 

 them, somewhat in the same manner as occurs on the arctic 

 side of the shores of Newfoundland. 



In the warm seas of the tropics, and particularly in the 

 Pacific and Indian Oceans, certain genera belong so con- 

 stantly to the deep water, that they can barely be considered 

 as seeking soundings ; such are chaetodons, balistes, and 

 acanthuri, delighting much to roam about the vertical coral 

 reefs and islands which abound in those latitudes, and often 

 have more than one hundred fathoms of water on their edge. 



tropical fish by this current may also induce an occasional phaeton to 

 pursue them. I have figured the variety of p. aethereus in this work from 

 one shot off New York. The specimen may be of a distinct species. 

 C. H. S. 



