414 U.8. NATIONAL MUSEUM BULLETIN 271 



size (in one genus, Jouhinella, gnathopod 1 larger than gnathopod 2) ; 

 uropod 3 biramous, outer ramus often reduced in size; telson short, 

 or of medium length, cleft. 



Relationship. — Most Haustoriidae lack a conspicuous rostrum but 

 intergradations occurring in genera such as Platyischnopus prevent 

 absolute distinction; many haustoriids have pereopod 5 as long as or 

 longer than pereopod 4 and of structure similar to each other, but 

 genera such as Pontoporeia have pereopods 4 and 5 like those of the 

 Phoxocephalidae. Those haustoriids having semblance of a rostrum 

 never have jDereopod 5 smaller and of different structure than 4 and 

 are restricted arbitrarily from the Phoxocephalidae. Probably the 

 families should be reorganized on the basis of pereopod 5 and by 

 disregarding the condition of the rostrum. 



Nomenclatural Changes in Phoxocephalidae 



Phoxocephalus capuciatus Oliveira (1955) is synonymized with Platy- 

 ischnopus gracilipes Schellenberg (1931). 



Seven species of Harpinia and Harpiniopsis are removed to Pseud- 

 harpinia; they have a basal ensiform process on antenna 2 and 

 distal spines or setae on the rami of uropod 2. 



Several other species of Harpinia lacking a basal ensiform process 

 on antenna 2 and presumably bearing elongate male antenna 2 are 

 removed to Harpiniopsis. 



Key to the Genera of Phoxocephalidae 



1. Article 2 of pereopod 3 more than twice as wide as article 3 (fig. 151c) . . .2 

 Article 2 of pereopod 3 about as wide as article 3 (fig. 151d) 10 



2. Palp of maxilla 1 biarticulate (fig. 150j) 3 



Palp of maxilla 1 uniarticulate (fig. 150i) 7 



3. Gnathopod 1 larger than gnathopod 2 and Eusirus-like (fig. 150o), man- 



dibular molar triturative (fig. 150e) Joubinella 



Gnathopods 1 and 2 similar in size, or gnathopod 2 larger than 1, mandibular 

 molar not triturative (fig. 150/) 4 



4. Palp article 4 of maxilliped bearing two stout distal setae, not claw-like, 



(fig. 150m), rostrum minute (fig. 149c) 5 



Palp article 4 of maxilliped not bearing large distal setae or bearing one nail, 

 claw-like (fig. 150n), rostrum well developed (figs. 149a,d) 6 



5. Mandibular molar vestigial, a small spinose protuberance . Microphoxus 

 Mandibular molar very large, minutely setulose (fig. 97d). 



Urothoides (Haustoriidae) 



6. Mandibular palp sickle-shaped, borne on a large process of the mandibular 



body (fig. ISOg) Mandibulophoxus 



Mandibular palp not sickle-shaped, not borne on a large process of the 

 mandibular body (fig. 150e) Paraphoxus 



