REPORT ON THE AMPHIPODA. 173 



' Hyale ' (Nicea), and is not therefore a generic character. HijalcUa is tlien a synonj'iue of 

 Allorcliestes." 



To the second paragraph of this quotation is appended tliis note : " § Doubtless a large number 

 of the species placed under Allorcliestes by Bate in his Catalogue of the Anijjhipoda in the 

 British Museum have in reality a divided telson. In fact, it would seem that the telson 

 is cleft in most of the marine forms, and such probably formed the bulk of Dana's original 

 genus Allorcliestes. The only types of Dana's species that I can discover are two specimens 

 of A. media in the JIuseum of Comparative Zoology. In these the telson is cleft to the 

 base. This, however, will not affect the synonymy as given above." 



There are, however, some considerations which Mr. Faxon does not appear to have taken into 

 account. He says that Hyale pontica was carefully described and figured with the posterior 

 caudal stylets two-branched (zur Fauna der Krym, p. 87, pi. v. figs. 20-28, 1836), but no 

 allusion to this feature is made in the generic character by Rathke (though Spence Bate 

 introduces it in his Catalogue), and in the description of the species Rathke's words are : — 

 " die Sprungbeine sind nur kurz und schwach ; das erste Paar ist am liingsten, jedoch 

 kurzer als das hinterste Paar der Afterbeine, das zweite ist noch kiirzer, und das letzte am 

 kleinsten : an den beiden ersteren Paaren sind die Aeste ungefahr so lang, als die Wurzel- 

 glieder, an den letzten aber bilden die Aeste nur zvvei sehr kleine 'warzenformige Vorspriinge 

 des Wurzelgliedes." Here we find that in the first and second uropods the rami are about 

 as long as the peduncles (not much shorter as the B. M. Catalogue makes out), but on 

 the last pair the rami form only two very small wart-like processes of the peduncle. 

 Possibly this means onlij two to each peduncle, but I think that it more probably means 

 only two for the pair of peduncles. It is true that on PL v., Fig. 21, representing " das hinterste 

 Sprungbein," shows two rami to one peduncle, but this plate is signed " W. Pape del.," not as 

 on other plates in the same memoir, " Eathke del." This takes something from the force of 

 Mr. Faxon's expression, " the careful description and illustration of the founder of tjie 

 genus." Nevertheless with only these facts in view I should accept Mr. Faxon's ruling. 

 But in his later work, B. z. Fauna Norwegens, pj). 81-83, Eathke describes, under the name 

 " Amphithoe Prevostii, M. Edwards ?," a species of which he says " the pleopoda of the sixtli 

 pair are very small, and do not end with two rami, but each consists only of two joints, 

 tolerably thick in proportion to their length, of which the terminal joint is smaller than 

 the basal, and bears at the end some small spines. The back is quite smooth throughout." 

 He further says, " this animal is very nearly related to an Amphipod which I found in the 

 Black Sea and described under the name Hyale Pontica, but is distinguished from it chiefly 

 by the want of a telson." At the end of his book, p. 26-l:C, he has made up his mind that 

 the species is new and names it Amphithoe. nilssonii. He thought it a question (p. 83) 

 whether this species and Hyale p)ontica ought not to form a new genus, on the ground that 

 the second gnathopods were so different from those of the Amphithoe species as then 

 accepted. His ascribing to Amphithoe nilssunii the want of a telson was of course due only 

 to an oversight or an accidental defect in his specimen, but he says nothing of distinguishing 

 it from Hycde pontica by the difference of the last uropods. Amphithoii fiilssonii is trans- 

 ferred by Spence Bate to the genus Allorchestes, while Amphito'e Prevostii oi Milne-Edwards 

 he assigns to Nicea, although when he saw the type specimen he considered it " synonymous 

 with Nilssonii of Rathke, but unfortunately omitted to observe the character of the telson," 

 B. j\I. C, p. -53. Now if Hyale pontica really has two rami to the peduncle in the last 

 uropods, that one little extra wart will cut it off from the family of the r'rchebtidfe, in which 

 the last uropods are uni-branched. Yet there is nothing else to distinguish it from that 

 family. Its antennae, its gnathopods in both sexes, its general shape both of the body at 

 large and the pleon in particular, wall identify it with the Orchestida\ It.s habitat among 

 stones and mussels on the beach, its colouring, clear bottle-green .•-hading into brown, it."; 



