66 ME, GEOFFKEY WATKIN SMITH ON THE 



interfered with the construction of the dam. Under logs and the fallen leaves of the 

 beeches, the Hopper (Talitrus sylvaticus) was very abundant. In a little rivulet I 

 collected some specimens of the Amphipod Gammarus australis. — (2) Near the top of 

 Mt. Read, at an elevation of about 3000 ft., I visited a tarn of exceedingly deep and 

 clear water. In this tarn Anaspkles tasmania? was fairly abundant and a species of 

 Neoniphargus, If. alpinus, sp. n. (PI. 14. figs. 13-16). The water swarmed with the 

 little red Copepod Boeckella rubra (PI. 18. fig. 1), so that the fauna of this tarn closely 

 resembled that of the tarns on the Harz Mountains. I was surprised here by the 

 quantity and tameness of the Platypus, which swam round our raft with the greater part 

 of their bodies exposed to view — no doubt owing to their little acquaintance with human 

 beings, as the tarn had only been visited at long intervals on two or three occasions by 

 miners. 



General Remakes on Geographical Distribution. 



From a zoological and botanical standpoint Tasmania belongs to what Professor 

 Baldwin Spencer (' Narrative of the Horn Expedition to Central Australia,' 1895) has 

 called the Bassian Subregion of Australia, which includes Tasmania and Victoria south 

 of the Dividing Range of mountains. This subregion is characterised by a moderate or 

 great rainfall and a temperate climate. 



The freshwater Crustacea of Tasmania are for the most part represented by closely 

 allied or, in some cases, identical species on the mainland of Victoria, and very few of 

 the commonest and most typical forms (e. g. Anaspkles, Phreatoicus, Chiltonia, Neoni- 

 phargus, Gammarus, Boeckella) range north of the Dividing Range into tropical or 

 subtropical Australia. These characteristic genera of Southern Australia belong, in fact, 

 to an essentially temperate fauna, by far the greater number of species being found on 

 the high alpine ranges of Tasmania and on the slopes of the Dividing Range of Victoria 

 and New South Wales. They are, however, again represented by closely allied species 

 in the temperate climate of New Zealand, especially in the subterranean waters of that 

 island (Chilton, Trans. Linn. Soc. London, ser. 2, Zool. vol. vi. pt. 2, p. 163). These 

 facts are of the greatest importance in considering the probable derivation of this fauna. 



Two of the most characteristic genera of the Tasmanian freshwaters, viz. the 

 Amphipod Chiltonia and the Copepod Boeckella, which also occur in the temperate 

 parts of Southern Australia, are represented not only in New Zealand but also in 

 temperate South America, where Boeckella has been several times recorded (see Daday, 

 Termes. Piizetek, Bd. xxi. 1902, p. 201) and Chiltonia is replaced by the closely allied 

 Myalella of Lake Titicaca and the southern ranges of the Andes. These two genera 

 [Chiltonia and Boeckella) are therefore confined in their distribution to the temperate 

 parts of the Southern Hemisphere, with the exception of S. Africa. The Copepod 

 Boeckella occupies the same position in the Southern Hemisphere as Diaptomus in the 

 Northern, which in the south it almost entirely replaces. Although some of the species 

 occur in small ponds, the majority live in lakes and are particularly characteristic of the 

 cold highland tarns of Tasmania. The Parastacine group of Crayfishes has a similar 

 distribution, being found in New Zealand {Paranephrops), Tasmania and Southern 



