90 GAMMARIDJ2. 



A M PHI POD A . L YSIA NA SSIDES. 



NATA.TORIA. 



Genus ANONYX, KROYER. 



Anonyx Kroyer. GRONLAND, Amfip. p. 15 ; Nat. Tidsk. v. ii. p. 256. 



Generic character. Superior antennae short, pyriform, furnished 

 with a secondary appendage. Mandibles having a smooth 

 incisive margin and a palpiform appendage. First pair of 

 gnathopoda subchelate ; second pair long, slender, feeble, and 

 subchelate. Telson single, squamiform, cleft. 



THIS genus was separated from Lysianassa b} 7 Kroyer, 

 from the subchelate form of the hands of the third 

 pair of limbs (" parvulo instructi ungue"\ and from the 

 fourth pair of limbs being destitute of a terminal hook, 

 (whence the generic name,) the place of which is sup- 

 plied by a brush of hairs. Also the middle tail-piece, 

 instead of being entire, as in Lysianassa, is divided more 

 or less deeply in Anonyx. Neither of these characters 

 are capable of being distinguished without close exami- 

 nation, and in some species, Anonyx lagena for example, 

 the extremely oblique palm of the hand approximates, 

 in its form, to that of a Lysianassa ; again, the divi- 

 sion of the central tail-piece is occasionally so slight, 

 as in A. obesa, that a small depression alone exists. 

 The genus Opis, of which Kroyer has described two 

 species, diifers from Anonyx in the opposite extreme. 

 As Lysianassa has a less perfectly chelate hand than 

 Anonyx, so Opis possesses one that is still more perfect 

 as a didactyle claw. 



This grouping, although convenient, appears to us to 

 be arbitrary ; moreover, it is not improbable that some 

 of the forms may be only sexual. 



