422 U.S. NATIONAL MUSEUM BULLETIN 271 



3. Gnathopods simple, slender (fig. 153o) Parepimeriella 



Gnathopods subchelate, stout (figs. 15Sl,m) 4 



4. Rostrum less than one fourth as long as article 1 of antenna I. 



Pleusymtes, new genus 

 Rostrum nearly as long as article 1 of antenna 1 Mesopleustes 



5. Maxillipedal palp article 3 bearing a distal process (£g. 153i) 6 



Maxillipedal palp article 3 lacking a distal process (fig. 153A) 7 



6. Uropod 3 with a large peduncular process supporting the rami (fig. 1535) • 



Austropleustes 

 Uropod 3 lacking accessory peduncular process Neopleustes 



7. Gnathopods with distally bent, slender, tapering sixth articles, essentially 



simple (fig. 72o) Harpinioides ' 



Gnathopods subchelate, with ovate or subrectangular, unbent sixth articles . 8 



8. Antennae short, gnathopods bearing lobate article 5 (fig. 153m) . Pleustes ^ 

 Antennae long, gnathopods usually lacking lobate article 5 (fig. 153p). 



Parapleustes ^ 



• See this genus in the Calliopiidae. 



2 The diSerences between Pleustes and Parapleustes are subjective. See Barnard and Given (1960, p. 39) 

 for discussion. 



Genera of Pleustidae 



Austropleustes K. H. Barnard 



Austropieustes K. H. Barnard, 1931; 1932. 



Type-species: A. cuspidatus K. H. Barnard, 1931 (original desig- 

 nation) ; 1932. 



Mandibular molar a small smooth protuberance; article 3 of maxil- 

 lipedal palp distally produced; gnathopods slender but subchelate; 

 uropod 3 with a large peduncular process supporting the rami (Neo- 

 pleustes). Species: 2, antarctic, deep littoral. 



Mesopleustes Stebbing 



Mesopleustes Stebbing, 1899d; 1906. 



Type-species: Pleustes abyssorum Stebbing, 1888 (original desig- 

 nation) . 



Mandibular molar well developed, ridged; article 3 of maxillipedal 

 palp not distally produced; gnathopods subchelate; rostrum nearly 

 as long as article 1 of antenna 1 {Pleusymtes). Because lower lip is 

 not typical of other pleustids this genus probably should be assigned 

 to the Calliopiidae, noting that it also has affinities mth Param- 

 phithoidae because of the tendency of the coxae toward acumination. 

 Species: 1, probably cosmopolitan, bathyal-abyssal. 



