238 Transactions.— ZoologT/. 



setosus in 1873, was not then able to consult "White's descrip- 

 tion of P. zealandicus, or he would probably, he tells me, not 

 have described his as a new species. I have, in my paper 

 already referred to, discussed to some extent the proba- 

 bility of the identity of these tw^o species, but at that time I 

 was unable to give a decisive opinion on the matter, owing 

 to the want of a sufficiently large collection to examine ; and 

 it was chiefly with a view of finally settling the question that 

 I undertook the present investigation. 



It is somewdiat difficult to compare the descriptions of P. 

 setosus and P. zealandicus, as they do not run exactly parallel ; 

 the differences, however, have been clearly stated by Miers,''' 

 who was able to examine the type-specimens of P. zealandicus in 

 the British Museum, and to compare them with a specimen of 

 P. setosus, Hutton. In speaking of P. zealandicus he says, 

 ■" This species is certainly distinct from P. setosiLS, Hutton. 

 In P. zealandicus, of wliich the type-specimens are in the 

 British Museum collection, the hands are clothed externally 

 with tufts of hair, arranged in longitudinal series, and are 

 armed with spines only on the superior margins ; and the 

 sides of the carapace are smooth. In P. setosus there are 

 spines arranged seriately upon the external surface as well as 

 the upper margin of the hand, and the branchial and hepatic 

 regions of the carapace are armed with numerous unequal 

 conical spines." 



I have specimens, from streams at Dunediu, that agree 

 fairly well with the description of P. zealandicus as given in 

 Miers's catalogue ; and, though they differ to some extent from 

 tyjncal specimens of P. setosus, the characters in which they 

 differ vary, as I shall show in detail further on, to a large 

 extent according to size and age, even in specimens taken 

 from the same stream, and such a complete series of transi- 

 tional forms is found that it will, I think, be necessary to 

 combine the two species under the name P. zealaiidicits, 

 which has priority over P. setosus by many years : but, in ac- 

 cordance with the rule suggested by Professor von Martens, 

 and adopted by Professor Hutton, and by Mr. G. M. Thom- 

 son and myself,! the name umst be written Paranephrops 

 neo-zelanicus. 



The differences between specimens of P. 2^^<^nifro7is of dif- 

 ferent ages and localities are quite as great as those between 

 different forms of P. neo-zelanicus ; so that, if the latter species 

 were divided, it would be necessary to divide the former also. 



The only other reference to two species of Parane2')hrops 

 from New Zealand besides P. ■planifrons that I can find is an 



* " Ann. and Mag. N. H.," ser. 4, vol. xv., p. 412, 



t See " Trans. N.Z. Inst.," vol. xvi., p. 187, and vol. xviii., p. 141. 



