294 



C. SKOTTSBERG 



and penguins are occasionally seen around the islands but do not breed 



there. 



Of the 15 species breeding on the islands 3 are endemic; of the remaining 

 12, 6 are represented by endemic subspecies of which, however, 2 also breed on 

 the Desventuradas Islands. Including these, 60% of the birds are endemic, a high 

 figure in animals as mobile as birds are. Otherwise, the poverty of the island ornis 

 is noteworthy, as also the fact that the affinities of the landbirds are all with 

 S. America. 



With regard to the actual distribution we can distinguish the following two 



groups. 



I. South American (especially Chilean) group. — 10 sp. 



a. Endemic (6): Anaeretes fernandezianus, Aphrastura masafuerae, Euste- 

 phanus fernandensis, Cinclodes oustaleti baeckstroemii, Cercneis sparverius fer- 

 nandensis, Buteo erythronotus exsul. 



/;. Not endemic (4): Turdus magellanicus, Eustephanus galeritus, Asio flam- 

 meus, Puffinus creatopus. 



II. South Pacific group. — 5 sp. 



a. Endemic (3): Pterodroma externa externa, cooki defilippiana and cooki 

 masafuerae. 



b. Not endemic (2): Fregetta grallaria, Pterodroma neglecta. 



The first group includes of more tropical birds Aiiaerctcs, Cine/odes and Eii- 

 stephamis, and of more temperate lurdics, Asio, CercJmeis, Buteo and Ptiffimis. 

 Of the endemic species EustepJtanus fernandensis is the most notable, in certain 

 characters a unique type in the family Trochilidae. The second group is of par- 

 ticular interest as including, beside the widespread frigate-bird, four species of 

 Pterodroma not breeding on the mainland, where, perhaps, a special race of 

 P. cooki breeds. The genus is essentially austral-circumpolar, as it were tricentric, 

 with Tristan da Cunha representing the African sector. Cases like those o{ P. neglecta 

 and externa call for a common source and suggest that Pterodroma belongs to 

 an Antarcto-tertiary element which inhabited the coasts and islands of Antarctica 

 n preglacial tim23. 



Oligochaeta. 



M1CII.A.ELSEN [181) regards all the earth-worms of Juan Fernandez as adven- 

 titious. The single strictly South American Kerria saltejisis was, he believes, in- 

 troduced from Chile with the human traffic, and this is also true of the three species 

 of Allolobophora, introduced to Chile from PLurope, and by Friedcricia galba. The 

 occurrence of l^achydrilus vej-rncosiis offers more interest. It was known from Great 

 Britain, the Hebrides, S.W. Africa and Fuegia, everywhere living on the seashore; 

 on Masatierra it was not found on the beach but inland in a freshwater stream. 



Hirudinea. 



The leech discovered in 19 17 in the highland of Masafuera was described 

 as a new species of the Australian genus Philaernon, Ph. skottsbergi L. Joh. [147). 



