114 U.S. NATIONAL MUSEUM BULLETIN 271 



Mouthparts from lateral view not conically grouped below head, uropod 3 

 degraded, coxae 1-4 not forming lateral shield, splayed laterally, body 

 depressed, rugose (fig. 10) phliantidae (p. 405) 



Mouthparts from lateral view not conically grouped below head, uropod 3 

 biramous and well developed, coxae 1-4 compressed, very short, not 

 forming lateral shield, body compressed, smooth. 



Parahalice (Pardaliscidae) (p. 403) 



SECTION G 



1. Maxillipedal palp with fewer than four articles 2 



Maxillipedal palp with four articles 3 



2. Maxillipedal palp 3-articulate. 



(fig. 7) (exceptional) acanthonotozomatidae (p. 117) 



Maxillipedal palp 2-articulate (fig. 6) lafystiidae (p. 281) 



Maxilliped lacking palp (fig. 5) ochlesidae (p. 371) 



3. Mouthparts from lateral view conically grouped below head 4 



Mouthparts from lateral view not conically grouped below head .... 5 



4. Anterior coxae long, some acuminate ventrally (fig. 7). 



acanthonotozomatidae (p. 117) 

 Coxae short, not acuminate ventrally (fig. 28) . 



Halicella (Pardaliscidae) (p. 402) 



5. Gnathopod 1 carpochelate (fig. 21) leucothoidae (p. 289) 



Gnathopod 1 propodochelate, subchelate, or simple 6 



6. Mandibular molar present (though occasionally very minute) 7 



Mandibular molar absent 22 



7. Pereopod 5 shorter and of different structure than pereopod 4, head with 



strongly depressed large rostrum. 



(fig. 44) (exceptional) phoxocephalidae (p. 412) 



Pereopod 5 of structure similar to pereopod 4, rarely shorter than 4, rostrum 



if present not depressed (not dorsoventrally flattened) 8 



8. Telson elongate, more than twice as long as urosomite 3 9 



Telson short, subequal to or shorter than urosomite 3 (seen laterally) . .10 



9. Accessory flagellum 1-articulate ; antennae with large calceoli; gnathopods 



large and strongly subchelate (fig. 92h) . 



Eusirella (p. 225) and Eusiropsis (Eusiridae) (p. 225) 



Accessory flagellum multiarticulate ; antennae lacking calceoli; gnathopods 



feeble (fig. 167) synopiidae (p. 454) 



10. Pereopods 3-5 fossorial (some setae of those pereopods at least half as long 



as longest article of any pereopod, fig. 45) 11 



Pereopods 3-5 not fossorial (setae and spines very short, scarcely exceeding 

 article 3 of those pereopods) 12 



11. Accessory flagellum 1-articulate and extremely small, or absent; pereopod 



5 very elongate, at least 1.5 times as long as pereopods 3-4 (uropod 3 

 always elongate, rami very slender and lanceolate, subequal to peduncle, 

 but uropod 3 often broken, telson always short, linguiform and entire or 



emarginate) (exceptional) oedicerotidae (p. 373) 



Accessory flagellum rarely vestigial (if so, uropod 3 very short, flabellate, 

 rami highly unequal), pereopod 5 shorter than or usually scarcely longer 

 than pereopod 4 (uropod 3 usually with short peduncle, unequal rami 

 one of which longer than peduncle, if not then accessory flagellum multi- 

 articulate, telson cleft even minutely, usually elongate) . 



(exceptional) haustoriidae (p. 248) 



