Chilton. — On Neio Zealand Freshicatcr Crayfish. 239 



incidental one by Wood-Mason. Speaking of the parasite 

 {Temnoccpkula) '■'• found on these crayfish lie says, t " I 

 have since received from my friend Mr. W. Guise 

 Brittan, of Christchurch, New Zealand, an abundant 

 supply of each of tivo species ]; of crayfish from the rivers 

 Avon and Waimakariri respectively." (The italics are 

 mine.) 



In consequence of this notice I was exceedingly anxious 

 to get specimens from the Waimakariri to compare with the 

 Avon species, to see whether they differed or not ; but for a 

 long time I was unsuccessful. However, in September, 1885, 

 one of my pupils brought me specimens, not, indeed, from the 

 Eiver Waimakariri itself, but from a creek at Kangiora that 

 empties into one of its branches. These specimens, though 

 differing in some respects from the typical specimens of P. 

 setosus, and therein approaching the Dunedin specimens, 

 are not sufficiently distinct to be considered a separate 

 species. I have therefore no doubt that Wood-Mason's 

 specimens all belonged to the one variable species — P. neo- 

 zelanicus. 



While examining into the identity of P. setosus and P. 

 zealandicus I have at the same time examined and compared 

 with them specimens of P. planifrons from various localities, 

 and find that most of the points of difference hitherto given 

 break down when a large number of specimens is examined, 

 and that it is exceedingly difiicult to find constant characters 

 by which to separate them. At one time I was almost 

 tempted to combine the two species (P. i)lanifrons and P. 

 neo-zclanicus) into one; but, in consideration of the distinctness 

 between extreme forms, I have thought it best to keep them 

 as two species, though with some intermediate specimens it is 

 sometimes hard to decide which species they should be referred 

 to. The various differences will be given in the detailed de- 

 scription further on, but for the sake of greater clearness I will 

 briefly mention some of them here. The squame of the an- 

 tenna is generally larger in P . planifrons than in P. neo-zclanicus, 

 usually reaching slightly beyond the extremities of the ros- 

 trum and of the peduncles of the antennules and antenna ; 

 but this character fails us in some specimens from Wellington 

 and Pelorus Valley, &c. The sides of the carapace in P. j;/a»/- 

 frons do not, as a rule, bear so many or such well-developed 

 spines as in P. nco-zelanicus ; but the general arrangement is 

 much the same, and some specimens of P. planifrons (as, for 



* See below, Art. xxix. 



t "Ann. and Mag. N. H.," ser. 4, vol. xv., p. 336. 



* He gives the name of one species only, however — viz, Astacoides 

 zealaiulicus—Parancjjhrops setosus, Hutton. 



