206 A HISTOEY OF RECENT CRUSTACEA 



tices have been followed, in some stages of society, by 

 human beings themselves. 



Phoberus, A. Milne-Edwards, 1881, has the eyes close 

 together, small, and implanted on short rudimentary eye- 

 stalks. The scale of the second antennae is large. The 

 first pair of trunk-legs are long, slender, and cylindrical ; 

 the second and third more slender and not quite so long ; 

 the fifth slightly subchelate. In Plioberus tenuimanus, 

 Spence Bate, from New Guinea, the entire surface of the 

 animal is spinous. 



Nephropsis, Wood-Mason, 1873, has the eye-stalks 

 small, the second antennae without a scale, the first pair of 

 trunk-legs large, the second slender, the third slender and 

 with the chelte minute, the last two pairs slender and 

 simple. All the recorded specimens have been taken at 

 great depths, from two or three hundred down to eight 

 hundred fathoms. The type-species, Nepliropsis Stewarti, 

 Wood-Mason, from the Andamans, was supposed to be 

 blind, but, according to Spence Bate, ' it appears both 

 from Wood-Mason's own figures and from an examination 

 of the Challenger specimens, that this genus cannot be 

 described as being without organs of vision.' Nepliropsis 

 atlantica, Norman, from the Faro Channel, has small and 

 immature eyes. 



Eutrichocheles, Wood-Mason, 1876, was instituted to 

 receive the Cancer modestus of Herbst from India, which, 

 according to Wood-Mason, is ' especially interesting as 

 being the nearest known blood-relation of the remarkable 

 blind crayfish,' Nephropsis Stewarti. 



Family 3. Potamobiidce. 



The carapace is sub-cylindrical, with a pronounced 

 rostrum. The fourth and fifth pairs of trunk-legs are not 

 chelate. The outer branch of the uropods has a transverse- 

 suture. The first maxillipeds have an epipod devoid of 

 branchial filaments ; the second maxillipeds and the first 

 three pairs of trunk-legs have the podobranchitc always 

 iprovided with a plaited lamina. None of the branchial fila- 



