202 A HISTORY OF RECENT CRUSTACEA 



NepKwps, Leach, 1819, has the eyes wider than their 

 foot-stalks and reniforni or kidney-shaped in accordance 

 with the meaning of the generic name. The scale of the 

 second antennae is large, reaching the end of the peduncle. 

 The first pair of trunk-legs are long, slender, and pris- 

 matic in shape, not very unequal. The type-species, 

 Nephrons norwegicus (Linn.), is distributed generally 

 through the seas of Europe, belonging not only to Nor- 

 way, but also to Great Britain and the Mediterranean. It 

 is a beautiful species both inform and colouring. Accord- 

 ing to Spence Bate, the branchial arrangement is identical 

 with that of the common lobster, but Huxley draws a 

 slight distinction, saying that ' the branchial plume of the 

 podobranchiae of the second maxillipeds is small or absent, 

 so that the total number of functional branchisB is reduced 

 to nineteen on each side' in Nephrops, as compared with 

 twenty in the lobster. 



Sars has figured and described the ' second larval stage ' 

 (see Plate IX.),' the ' last larval stage,' and the ' first post- 

 larval stage ' of this species. The larval pleon is highly 

 remarkable, not so much on account of the great dorsal 

 spines that arise from the fourth, fifth, and sixth segments, 

 as of the telson, which spreads itself out into two ciliated 

 and spinulose spine-like branches, which together make its 

 arch equal in breadth to the length of the animal. 



A second species, Nephrops Thomsoni, Spence Bate, 

 has been taken between Australia and New Zealand, and 

 in the Philippines. 



Eunejyhrops, S. I. Smith, 1885, is very near to 

 Nephrops, except that, like the American lobster, it has a 

 well-developed podobranchia to the second maxillipeds, 

 and the scale of the second antennae is very small. The 

 type species, Eunephrops Bairdii, was taken in the 

 Caribbean Sea. 



Astacns, Leach, 1814, has the eyes not wider than the 

 foot-stalks and subglobose. The scale of the second an 

 tennae is spine-like, not reaching the end of the peduncle. 



' The form norrerjievs, accidentally use(^ on the Plate, is not tlia 

 original spelling, but a later refinement. 



