Astacoides and Paraneplirops. 41,'] 



the typical species P. plamfrons, wliicli is also the comniouest 

 species of the genus, the body is comparatively slender, the 

 anterior legs elongated, with the palm more than twice as long 

 as broad, and clothed externally with longitudinally seriate 

 tubercles and spines ; moreover the antennae are inserted ex- 

 ternally to the antennules, and are furnished with a very large 

 basal scale, which is longer than the peduncle of the antenna. 

 It is true that in other species of both genei-a (as, for example, 

 Astacoides serrafus, Shaw, and A. FranhUnn, Gr^ay, from 

 Australia, and Faranephrops zealandicus^ Wliite) the distinc- 

 tive characteristics are somewhat less strongly marked ; but, 

 so far as the materials in the collection of the British Museum 

 afford means of comparison, I can see no necessity for uniting 

 the genera. 



Professor Wood-Mason refers, I believe, to Paranephrops 

 zealandicus j^hiiQ* , in speaking of ^^ Astacoides zealandicus 5" 

 but this species is certainly distinct from P. setosus, Huttonf. 

 In P. zealandicus, of which 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 upon 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. A specimen agreeing well with Button's 

 description is in the National collection. 



I may say in conclusion that a somewhat analogous mode 

 of attachment has been observed among the Edriophthalmata, 

 in the case of the young oi Arcturus, by Sir J. G. Dalyell, 

 whose account is quoted by Messrs. Spence Bate and West- 

 wood in their ' History of the British Sessile-eyed Crustacea,' 

 ii. p. 370. In this genus the young individuals affix themselves 

 in clusters to the antennas of the mother, clasping the peduncles 

 of those organs with their prehensile three posterior pairs of 

 pereiopoda; and a specimen of ^. Baffini actually exhibiting 

 this mode of attachment is preserved in the collection of the 

 British Museum. The young specimens are clustered chiefly 

 on the underside of the antennae, with the head pointing to- 

 ward the body of the parent. In this instance no specially 

 modified prehensile organ exists, nor, indeed, is such required. 



* Astacus zealandicus, White, P. Z. S. 1847, p. 123, Auu. & Mag. Nat. 

 Hist. ser. 2, i. p. 225 (1848) ; raranephrops zealandicus, Miers, Zool. Ereb. 

 & Terr., Crust, p. 4, pi. ii. fig. 2 (1874), Cat. New-Zeal. Crust, p. 73 (1870). 



t Ann. & Mag. Nat. Hist. ser. 4, vol. xii. p. 402 (1873). 



