14 REPORT — 1842. 



the 34-th parallel, within which little or no rain falls. We can trace this zone 

 from Pitis and Lower California across the new world to the Atlantic. In 

 the old world it includes the Sahara and lesser deserts of Northern Africa, 

 Egypt, Arabia Deserta, and certain districts in Asia, being interrupted chiefly 

 by the intrusion of lofty mountain chains. This arid belt is bounded by 

 zones of periodic rains, which on the north side of it fall in the winter season, 

 and on the south side in the summer only, the rains having a more uniform 

 character in the latter district. Similar zones exist in the southern hemi- 

 sphere, though they are less easily traced from the intervention of large tracts 

 of ocean. We find them well characterised however both on the Pacific 

 and Atlantic coasts of South America, again north of the colony of the Cape 

 of Good Hope, and in the southern half of New Holland, where as at the 

 Cape the rivers are for the most part mere chains of ponds. Some provision 

 must be made for the preservation of fish inhabiting the ponds in such coun- 

 tries, in the dry season ; and we observe, accordingly, that in Australia vari- 

 ous Cheironectes, Batrachi, Gobioides, Megalapes and Apocles bury themselves 

 in the mud as the water dries up, and like the lepidosiren of the Gambia re- 

 main in an inert state until the rain falls. In South America some siluroids, 

 such as the Callichthys, also bury themselves in the mud, while the Doras 

 hancochi when the water fails marches overland in dense bodies in quest of 

 another river. The Anabasidece have a peculiarity in the structure of the 

 pharynx enabling them to retain a supply of water in seasons of drought, which 

 has been compared by some authors to the water-bag of the camel, that 

 ship of the desert. These fish are most abundant in the southern parts of 

 Asia, a few range to the Indian archipelago, and the genus Spirobrcmchus 

 peoples the rivers of the Cape of Good Hope. The Indian Anabas, a member 

 of the family, is said to ascend palm-trees in quest of little pools of water to 

 be found in the axils of the leaves. None of the group have as yet been de- 

 tected in Australia, though the nature of the country would lead us to ex- 

 pect to find them there : but the rivers have been scarcely explored by the 

 ichthyologist. As to New Zealand, its maritime, and consequently more humid 

 climate, seems to render any peculiarity in the structure of the respiratory 

 apparatus of its fresh-water fish less necessary. With regard to the marine 

 fish the proportion of known species is as I have already said too small to en- 

 able us to draw any very precise conclusions ; but we cannot fail in reckoning 

 the known Australian fish (including those of New Zealand) to be struck with 

 the unusual number which are furnished with simple pectoral rays, more or 

 less divided from the rest of the fin. The cottoid family, in which this struc- 

 ture is predominant, is as numerous, if not more so, in the Australian seas, as 

 in the corresponding latitudes of the northern hemisphere, and there are in 

 addition many Polynemi, Ckeironemi, Aplodactyli, Cheihdactyli, Nemadac- 

 tyli, and Latres, all furnished with simple pectoral rays. Many Australian 

 genera exist also in the seas of China. Of the Cyprinoids which are so 

 very abundant in India, but one species is known to exist in Polynesia or 

 Australia. 



In the following list " Solander" refers to that naturalist's manuscript ' Pisces 

 Australia^,' containing his descriptions of the New Zealand fish obtained on 

 Cook's first vuyage. The term " Australia" as used by him relates solely to 

 New Zealand, which was supposed until Cook circumnavigated it, to be part of 

 a great southern continent. The figures of fish executed in the same voyage 

 are quoted under the name of the artist " Parkinson". " G. Forster" indicates 

 the drawings made on the second voyage, which are preserved with those of 

 Parkinson, and Solander's manuscripts in the Banksian library. " J. R. Forster " 

 refers to the description of the species in Schneider's edition of Bloch. Forster's 



