of the Crustacean Family Ilippolytiihu. 33 



lie f^ivcs as the type sp(»cie.s //. Fahricli, which has a typical 

 Spironlocaria mandible. 



TI>e type of Spenco Hate's Iletairus is a species which he 

 describes under the name //. Gaiinardii (.M.-I<j.), but which 

 Aliss Rathbun (ilarriman Alaska Exped. x. p. 73, li).)i) 

 identifies, no doubt correctly, as //. polavis (Sabine). 



So far as I can gather from the description of Birulia, 

 which Mr. W. F. Kirby has kindly translated from the 

 Russian for me, the genus differs from Spirontocaris only in 

 the characters of the carapace and rostrum. 



Genus Latreutes, Stimpson. 



Zn/rej/^<?«, Stiiupsm, Pric. Acid. Philal^lplii.i, 1803, p. 27; Spence 

 Rite, Cliall. licp., Macriira, p. oSl. (TypN L. ensifents, M.-Ehv.) 



Plati/hfma, Speiu-e Bate, Cliall. Uep., .Macnira, p. 578. { = Ci/clo- 

 rhiftichn.^, de Ilaau, Rhynchocyclus, Stiinpsoij. Type, P. planirostris, 

 de ilaaa.) 



As Ortraann has pointed out (Zool. Jahrb., Abtli. f. Syst. 

 V. p. 505, 18'Jl), there seems to be no valid reason for 

 regarding the two species mentioned above as belonging to 

 distinct genera. They agree in having the carpus of the 

 second legs composed of three segments and in such details as 

 the rounded lobe of the first segment of the antennules, the 

 acute antennal scale, and the serrated antero-lateral margin of 

 the carapace. Stebbing (Hist. Crust, p. 235) relies for their 

 separation on tlie statements of Spence Bate that the second 

 maxillipeds of Platyhenia are six-jointed and those of Latreufes 

 seven-jointed. This, however, is certainly not the case in 

 the two type species, both of which have the second maxilli- 

 peds identical in structure and composed of six segments. 

 Apart from the difference in general form, which seems to 

 liave been Stimpson's chief reason for separating the genera, 

 the only distinction which I can find is that, while in Platy- 

 hema the series of epipods extends to the penultimate pair of 

 legs, in Latreutes (contrary to Stimpson's statement) it ceases 

 at the third pair. Since Spence Bate names Ci/dorhi/nc/ius 

 planirostris as the type of Platyhemo, it is not legitimate to 

 use that generic name, as Ortmann has done, after transferring 

 its type species to Latreutes. 



Genus Trachycaris, gen. nov. 

 Type, Platybeina ruyosus, Speuce Bate, Chall. Rep., Macrura, p. 571). 



There can be no doubt that Spence Bate's P. rugosus is 

 generically distinct from de Ilaan's Cyclorhj/nchun plani- 

 rostriSf the type of the genus Pl<iti/bema. The followin<r 



Ann. d; Mag. N. Hist, Ser. 7. Vol. xvii. 3 



