426 U.S. NATIONAL MUSEUM BULLETIN 271 



Type-species: Amphithopsis malmgreni Boeck, 1871 (selected by 

 Chevreux and Fage, 1925). 



Mandibidar molar large, ridged; article 3 of maxillipedal palp 

 a[)ically produced; gnathopods subchelate. Species: 7, arctic-boreal, 

 littoral to bathyal. 



Podoceridae 



Figures 154-156 



Diagnosis. — Accessory flagellum variable, often absent; urosome 

 markedly dei)ressed, segment 1 more than twice as long as segment 2, 

 often considerably longer; telson entire; pereopods not glandular. 

 See Corophiidae, Cheluridae. 



Description. — Accessory flagellum variable, multiarticulate, ves- 

 tigial or absent; body variable, broadly depressed or slender and 

 subcylindrical, often carinate and toothed, urosome strongly de- 

 l)ressed, segment 1 more than twice as long as any following segment, 

 occasionally segment 6 apparently fused with segment 5, segments 

 5 and 6 reduced in length; coxae usually small and serially discon- 

 tiguous, occasionally splayed; mouthparts basic, except upper lip 

 slightly bilobed; gnathopods of medium size or large, subchelate; 

 uropod 1 normal; uropods 2 and 3: one or the other often missing, 

 vestigial or abnormal; uropod 3 biramous only in Icilius, generally 

 Avith one or no rami, telson circular or oval, short, entire; pereonites 

 6-7 coalesced in Dulichia and Paradidichia. 



Relationship. — The elongation of pleonite 4 distinguishes this 

 family from the Corophiidae. 



Podoceridae often have the subcylindrical bodies of Eophliantidae 

 and Colomastigidae but the latter two families may be distinguished 

 by their degraded mandibles lacking palps. 



Runanga J. L. Barnard (1961) is removed to the Corophiidae. 



Key to the Genera of Podoceridae 



1. Antenna 1 lacking accessory flagellum 2 



Antenna 1 bearing accessory flagellum 4 



2. Pleon with only five distinct segments preceding the telson (fig. 156a). 



Laetmatophilus ' 

 Pleon with six distinct segments preceding the telson (fig. 1566) .... 3 



3. Pleonite 5 carrying well-formed uropods Cyrtophium 



Pleonite 5 lacking uropods Leipsuropus ^ 



' See Dri/opoides (Aoridae or Ischyroceridae) bearing distinct uropod 3. 



2 Analysis of Leipsuropus may be defective; tiie loss of uropod 2 but the retention of uropod 3 seems il- 

 logical; the so-called third uropod may indeed be the second and this genus would then be referable to 

 Laetmatophihis. 



