'6 Mil. GlSOFFlfEY SMlTIi O.N THK 



practicable to fann these animals artiticially in ponds supplied with 

 I'unning water, such as are used at trout-hatcheries. In the 

 case of the marine lobster this is impossible, since the young 

 hatch out as larvse which at first live a pelagic existence ; but this 

 difficulty is absent from the culture of the Freshwater Crayfish, 

 tince the young leave the egg in a condition similar to the adult 

 and pass a certain amount of time after- hatching attached to 

 the swimmerets under the tail of the pai^ent. Much work would 

 have to be done upon the habits, food, rate of growth, etc., before 

 the undertaking could be placed upon a practical footing, but the 

 enquiry would be well worth undertaking. It may be suggested 

 that the best form for experimenting with would be the lai'ge 

 lasmaui?>n Crayfish (Astacopsis jWonklmii), which occurs in the 

 neighbourhood of Ijaunceston, and in this town there is already 

 a Covernment trout-hatchery which has been very successful. 

 One further' suggestion may be made : the Freshwater C.h'ayfish 

 industry in Cerman}', Russia,, France, and England has from time 

 to time l)een seriously damaged and in places extinguished by 

 the occurrence of a plague, probably of l)a,cterial nature ; it would 

 therefore be well to investigate the pai'asites of the form to be 

 cultivated and the best means of protecting it against bacterial 

 diseases, 



'There is a curious fact connected with the occun-ence an<l 

 nature of the large Crayfishes of Australia and Tasmania. The 

 genus Astacopsis is represented by three distinct species, each of 

 ■\\ hich occurs under two forms, a large and a small, which appear 

 to occupy different areas of distribution. 



Thus in 'J Msmania there is the large A .JranMinii {F\. XIV.), Avhich 

 is found only in the streams on the north and north-west coast, 

 near their entrance to the sea, and in these situations it appeal's 

 impossible to obtain small specimens. The small Tasmanian 

 Crayfish (PI. XV.) (var. A. iasmanicits), which cannot be sepa- 

 rated from the large form by any important charactei'S, save 

 that of size, occurs in the rBountaiir streams of the southern and 

 central part of the island, wher-e it breeds, but never grows to 

 more than about five inches in length. Parallel facts occur in 

 .1. serratus (PI. XVI.), which occurs as a large form in the 

 Murray and Pai-amatta llivers but is represented by smaller, less 

 spiny fornrs further inland (Pis. XVII., XVIII. ). A. kersharn 

 1 as a large form in the Moe River of Gippsland (PI. XIX.) and 

 a small foi'iu in the Xarracan (PI. XX.) and smaller streams. 



The most obvious explanation of this phenomenon is that the 

 large form, e. ;/. the lai'ge Tasmanian Crayfish, r-eally does breed 

 in the north coast streams arrd that its young stages in growth 

 are passed thei'e and could be found by assiduous search. The 

 oidy other alternative is that the young of the lai-ge form ar-e 

 always destroyed near the mouths of the rivers by Blackfish and 

 other predaceous forms which prey upon them, and that their 

 numbers are r-ecruited by a few individuals of the small mountain 

 forms which find their wav from the inland streains to the mouths 



