182 U.S. NATIONAL MUSEUM BULLETIN 2 58 



with unconstricted inner ramus; uropod 3 stout, short, peduncle 

 subequal to outer ramus, inner ramus about two thirds as long as 

 outer ramus, peduncle lamellar dis tola ter ally; telson linguiform, entire, 

 apex convex. Genus monotypic. 



Diagnosis of Parambasia forbesi Walker and Scott (1903). — 

 Upper lip and epistome undescribed; mandibles unclear; maxillae 

 not described; article 4 of maxillipedal palp apparently half as long 

 as article 3; gnathopod 2 with slight indication of chelation; coxa 

 1 very broad, apparently concealing all mouthparts, expanded dis- 

 tally; uropod 2 apparently with unconstricted inner ramus; uropod 

 3 relatively slender, rami slightly shorter than peduncle, latter with 

 scarce indication of becoming lamellar distally; telson linguiform, 

 entire, apex convex. 



The absence of notes on the upper Up suggests that it is inconspicu- 

 ous and perhaps fused with the epistome, as it appears to be in 

 Parambasia (?) rossii Stephensen (1927). Hurley (1963) writes that 

 this is true of New Zealand parambasias and suggests that 

 Psendambasia Stephensen (1927) is a synonym of Parambasia. 



The upper lip of Socarnella Walker (1904) is undescribed and that 

 genus cannot be related clearly to the other genera discussed herein. 

 It has been assumed from its name that the gills are strongly plaited 

 as in Socarnes. If they are not and the upper lip is socarnid-like 

 (=lysianassid-likealso) then £ocame^a could be relegated to Lysianassa. 



Parawaldeckia Stebbing, erected for Nannonyx thomsoni Stebbing, 

 which apparently is not a junior synonym of Lysianassa kidderi Smith, 

 differs from the known species of Lysianassa by the reduced inner 

 ramus of uropod 3, in resemblance to Nannonyx Sars. A new species of 

 Lysianassa to follow intergrades P. thomsoni and Lysianassa in the 

 condition of uropod 3 but the extreme reduction of the inner ramus 

 of P. thomsoni warrants a retention of the genus. 



Nannonyx Sars (see 1895) differs from the other genera being dis- 

 cussed by the complete fusion of the epistome and upper lip, the 

 lack of any sinus in that complex, and the slight protrusion of the 

 upper part of the complex in front of the lower part. 



Paralibrotus Stephensen (1923) has shortened articles 2 and 3 

 of the peduncle of antenna 1, the upper lip-epistome complex is inter- 

 mediate between that of Nannonyx and Lysianassa (in its lesser 

 projection and less clearly defined divisory sinus), the mandibular 

 palp is attached nearly level with the molar, and coxa 4 lacks a 

 postero ventral quadrate lobe. 



Key to Genera Related to Lysianassa plumosa 



1. Inner plate of maxilla 2 flabelliform Shoemaker el la 



Inner plate of maxilla 2 not flabelliform 2 



