6 W. LlLLJEBORG, 



more than one species can be named, that is common both to the Arctic 

 and Antarctic zones. This is the Falco peregrinus Lath., which has in- 

 deed received several different specitic names, as the slight varieties of co- 

 lour which it displays in widely separated localities, have by some ornitho- 

 logists been looked upon as indicating different species, though for our 

 own part we cannot but agree with Schlegel ') in considering these as me- 

 rely local varieties. The variety that occurs in North & South America has 

 been called Falco anatum Bonap., and the Australian form has been named 

 Falco mebinogenys GOULD. 



The fishes found in the fresh waters of Patagonia consist, it ap- 

 pears, only of two or three species of the Salmonoid family, as is also the 

 case with the fresh water fish belonging to the most northern fauna. 



Among the section of Mollusca are some instances which present the 

 phoenomenon of an extensive geographical distribution, though their capabi- 

 lities for locomotion are very limited. Thus for example the Tercbratnla 

 caput serpentis is found from Spitsbergen to the Mediterranean and on the 

 eastern coast of North America, and the Rhynchonella Psittacea from Spitz- 

 bergen and Greenland to England. Massachussets and Sitcha on the western 

 coast of N. America. Some species c. g. Secxicava arctica, 1 emts pullastra 

 and Pecten purio are found both on our northern coasts and at the Cape of 

 Good Hope though not in the intermediate tropical regions. We may per- 

 haps be able to show with certainty any species distinctly belonging to 

 the Arctic Zone, which also occurs in the Antarctic, though one or two 

 peculiar genera have been found that have their representatives in both 

 Zones. Hronn *) states that the species of Litnaeina which belongs to the 

 south Polar Ocean can not be distinguished from the Limacitta arctiea be- 

 longing to the northern, but it has by WOODWARD 8 ) been classed as a se- 

 parate species with the, name Limaeina antarctica. That genus has no re- 

 presentatives in the intermediate seas. The same is the ease with the ge- 

 nus of PunctureUa, which embraces two Species, of which the one belongs 

 to the arctic the other to the antarctic seas (in the neighbourhood of Tierra 

 del Fuego). Of the genus Clio we have in the northern Polar Seas the CHo 

 borealis, which is there found in such plenty as to constitute a considerable 



portion of the Greenland Whale's food. Passing over the intermediate oceans 



') Museum des Pay-Bas. 1 Livraisim. Falconcs. p. 1. 



') Klassen unci Orel nun yen des Thierreiche. 3. Bd. p. 648. 



*) Manual of the Mollusca p. L'uT. 



