296 Transactions. 



Both in collecting material and in the arrangement of this paper I was 

 given much valuable assistance by Dr. Chilton, to whom I wish now to 

 tender my sincere thanks. I have also to thank Dr. Benham, who offered 

 many helpful suggestions. 



Historical. 



The genus Paranephrops was created in 1842 by Adam White, who 

 described as the type species Paranephrops planifrons. " Dieft'enbach's 

 Travels," published during the following year, also contained a descrip- 

 tion of P. planifrons White, in which reference was made to supposed 

 resemblances to Nephrops. White again, in 1847. described a specimen, 

 collected by Mr. Percy Earl, under the name Astacus zealandicus. In this 

 paper he made no reference to Paranephrops planifrons, which he had 

 described five years previously. The species described as A. zealandicus 

 is clearly that now known as Paranephrops zealandicus. This description 

 of White's was republished in the following year in the ; ' Annals and 

 Magazine of Natural History." 



In 1852 J. D. Dana described a crayfish obtained from the Bay of 

 Islands, under the name Paranephrops tenuicornis. It had, on the squame 

 of the antenna, an inner apex not far from the end, " mostly concealed 

 by the fringe of plumose setae, which extends along the inner margin." 

 This feature is figured in his Atlas ; it will be referred to later in this paper. 

 In his " Classification of the Crustacea " (1859) Dana includes Paranephrops 

 under the Nephropinae, family Astacidae. 



In 1873 Captain F. W. Hutton described a new species of Para nephrops 

 which he named P. setosus. This species had a thorny-sided carapace, a 

 slight median ridge on its upper surface, the hand bearing spines and 

 numerous long hairs on its outer surface, and a broad flattened rostrum. 

 The habitat given was " stream near Invercargill, Province of Otago ; and 

 Biver Avon, near Christchurch, Canterbury." The specimen from Inver 

 cargill would probably belong to the species now known as P. zealandicus. 



Miers (1874), in the list of Crustacea of the " Erebus " and " Terror " 

 expedition, mentions P. planifrons and P. zealandicus. He thought that 

 P. tenuicornis Dana and P. planifrons White were identical, and that the 

 form described by White (1847) under the name of 'Astacus zealandicus 

 should be referred to Paranephrops. 



J. Wood-Mason (1875), in a note on Temnocephala, an external parasite 

 found on these fresh-water crayfish, remarked that he had received from 

 Captain Hutton a series of specimens of the fresh-water crayfish lately 

 described by him in the " Annals and Magazine of Natural History " under 

 the name of Paranephrops setosus. He continues, " I have since received 

 from my friend Mr. W. Guise Brittan, of Christchurch, an abundant supply 

 of each of two species of crayfish from the Rivers Avon and Waimakariri 

 respectively ." The italics here are mine ; the question as to there being 

 distinct species in the Bivers Avon and Waimakariri will be discussed later. 

 In 1876 Wood-Mason exhibited before the Boyal Society of Bengal some 

 specimens of New Zealand crayfish to which he gave the name Astacoides 

 tridentatus, " from the presence of three spines on the inferior edge of the 

 rostrum." These specimens are now in the Indian Museum. 



In the same year he published a note on the " Mode of Attachment 

 of the Young of Astacoides zealandicus," which species, he said, was the 

 same as Paranephrops setosus Hutton; but Miers (1876) considered it to 

 be P. zealandicus. 



