GAMMARIDEAN AMPHIPODA 179 



Species with a strong modification of uropod 3 are: (1) L. jalcata 

 Stephensen (1933b) with the peduncle slightly lamelliform and 

 slightly shortened gnathopod 2 with a bulky palmar projection, 

 gnathopod 1 strongly subfalcate and uropod 2 lacking a constriction; 

 (2) L. hummelincki Stephensen (1933b), with uropod 3 strongly 

 shortened, the peduncle lamellar, gnathopod 2 minutely chelate, and 

 uropod 2 possibly with a slight constriction; (3) L. bonairensis Stephen- 

 sen (1933a) with uropod 3 in the male having the nonlamelliform 

 peduncle but the appendage being strongly shortened, gnathopod 2 

 minutely chelate, uropod 2 unconstricted, upper lip and epistome 

 together projecting equally, the lobe of the upper lip being shorter 

 than in other species of the genus. 



Other taxa presently assigned to Lysianassa are: (1) L. hypocrita 

 Kuffo (1953), highly aberrant in its greatly shortened fourth articles 

 of the maxillipedal palps and in the peculiar second maxillae, remi- 

 niscent of certain stegocephalids having a geniculately connected outer 

 plate; probably this species deserves generic recognition; (2) L. 

 anomala Nicholls (1938) with its apparently coalesced upper lip and 

 epistome lacking a demarcating sinus; probably this species is refer- 

 rable to Parambasia (if correctly conceived of by Stephensen, 1927). 



Except for the substitute model, L. plumosa, only L. cinghalensis 

 of those species assigned to Lysianassa, has any tendency to the 

 greatly elongated article 1 of the mandibular palp, but indeed it 

 forms a perfect intergrade between L. plumosa and the other species. 



A number of species in allied genera, some of which were assigned 

 formerly to Lysianassa are now discussed. 



Lysianassa bispinosa (Delia Valle, see Chevreux and Fage, 1925) 

 was transferred to Arugella by Pirlot (1939). Based on the type 

 species, Arugella heterodonta Pirlot (1936), the diagnosis of that 

 genus, in outline comparable to that of L. plumosa, would be as 

 follows : 



Diagnosis of Arugella Pirlot (1936).— Upper lip forming a lingui- 

 form lobe projecting in front of epistome; mandibular cutting edge 

 with a deep incision delineating a lateral boss, molar located rather 

 distally, small, subcorneal, setulose, palp attached quite proximal to 

 molar, article 1 not elongated, about half as long as article 3; inner 

 lobe of maxilla 1 lacking long distal setae, bearing small setules, 

 outer lobe with 2 sets of spines, one set of normally serrated spines 

 and a smaller set of apically bifid spines; outer lobe of maxilla 2 

 about half as broad as inner; article 4 of maxillipedal palp about 

 15-20% as long as article 3, relatively stout; gnathopod 2 with mi- 

 nutely chelate palm; coxa 1 very broad but not concealing mouthparts, 

 expanded distally; uropod 2 with constricted inner ramus; uropod 3 



