210 A HISTOEY OF RECENT CRUSTACEA 



species that belong to Southern Brazil ; Pwranephrops, 

 White, 1831, is found only in New Zealand and (possibly) 

 Fiji, while even within the limits of New Zealand its two 

 species, planifrons and zealandicus, are found by Mr. Chilton 

 to have distinct and separate ranges ; Astacopsis, Huxley, 

 1878, and Engaus, 'Erichson, 1846, belong to Australia 

 and Tasmania, while Chceraps, Erichson, 1846, belongs to 

 Australia alone. Chceraps was instituted only as a sub- 

 genus by Erichson, and by Mr. Haswell it is united with 

 Astacopsis. Spence Bate, in remarking upon the peculi- 

 arities of distribution here set forth, speaks of ' the several 

 genera being adapted each to its own locality, no two 

 genera being known to exist in one habitat,' but to support 

 this statement he assigns Astacopsis to Australia, Er^gceys 

 to Tasmania, and Chceraps to Van Diemen's Land, intend- 

 ing perhaps a just reproach to those who altered the name 

 of Van Diemen's Land into Tasmania. In fact the small 

 burrowing Engceus may be peculiar to that island, and, 

 if not, it is separated by rather subtle distinctions from 

 Astacopsis, so that the three genera in question form a very 

 united group, and it is singular that, while they agree 

 together in their branchial arrangement, they differ in that 

 respect from all the other genera in the two families under 

 discussion. The unnamed ' Australian Crayfish' of Huxley, 

 which sometimes reaches a length of twenty inches, is pro- 

 nounced by Mr. Haswell to be Astacopsis serratus (Shaw). 

 In Paranephrops zealandicus, Mr. Wood -Mason has ob- 

 served that the young are specially fitted for attachment 

 under the pleon of the mother. The specimens examined 

 were under a third of an inch in length. The two hind- 

 most pairs of legs have the sixth joint 'provided at its 

 extremity with a strongly hooked, exceedingly acute, 

 movable claw, and on the lower edge at the end with six 

 or seven sharp spines, against which the claw folds, and 

 thus forms a very efficient prehensile arrangement.' 



