444 Transactions. — Miscellaneous. 



on the ground of facts. ••■ Abstracting this Tertiary fauna, we 

 liave first to consider those types which undoubtedly have 

 their representatives in the Cretaceous period, such as snakes, 

 serpents, and Anura. Their distribution is pretty wide, and 

 especially on the Fiji Islands they are well represented. The 

 Lacertiche, whose remains are the geologically oldest of the 

 now-living groups of reptiles, reach further on to the east. Is 

 this chance ? If floating trees and icebergs were the means of 

 their transport, why, then, do they transport only such old 

 forms'? And has the transport of fresh-water molluscs, such 

 &s Limn<sa, Physa,\ &c., also been going on across the sea? 

 This is simply nnpossible, for salt water kills these inhabitants 

 of the fresh water immediately. The land molluscs of Polynesia 

 also belong to a very old group of the fauna. Widely dis- 

 tributed are species of Fupa, a genus already represented in 

 the PaliEozoic era, and all the other Nephroimeusta have the 

 simple generative apparatus without the dart of the Helicece. 

 Genera which, like Cnio, are known to have existed already 

 during the Jurassic epoch, reach as far as New Zealand, and 

 the Parastacida of the fresh water, which, according to Huxley, 

 must also be attributed to a Jurassic age, to Fiji. 



The fauna of East Polynesia has such a well-pronounced 

 Mesozoic character that the supposition of a very old Pacific 

 continent, breaking up in pieces more and more during the 

 Mesozoic era, may give us a natural explanation. And the 

 further we go westwards the more frequently we meet with 

 recent types- — in New Guinea the genus Sus and Muridcs ; 

 in Australia, besides Muridce, also Canis. The craving only to 

 make of Australia a laud completely without placental mam- 

 mals accounts for Canis dingo being considered as a race of 

 the domestic dog. This error has been settled definitely by 

 Nehring.| Canis no doubt belongs to the oldest Caruivora. 

 Species of Canis are found in India and Sumatra, and C. dingo 

 is as well a domesticated sporting-dog as Canis latrans of the 

 North American Indians, or C. ingcs of the old Peruvians. 



The reason why more recent mammals§ did not migrate 



* With regard to the bats, it is quite possible that they kept pace 

 with the Miirichp, which, according to Wallace, have also been represented 

 in New Zealand. 



t Species of Pliysa occur on the Fiji and Tonga Islands, besides 

 numerous species of Sitccinea, but the small islands seem to have been 

 rather unfavourable to the conservation of the fresh-water fauna. 



I Nehring, Sitzungsber. d. Ges. naturf. Freunde ; Berlin (1882), p. 67. 

 Zoolog. Garten (1885), p. 164. 



§ Another very surprising immigration is that of Mycetopus rugatus 

 of the Victoria River, in North Australia. In my opinion it origmates 

 from Asia, and not from South America, where Mycetopus originally 

 was missing in Archiplata. j\Iy Australian colleagues should see that the 

 anatomy and embryology of this species be studied, as it is still question- 

 able whether it belongs to 2Iycetopus s.-st?'. or not. 



