MARINE GAMMARIDEAN AMPHIPODA 301 



9. Article 2 of pereopod 3 deeply indentured (fig. 1316) or with very long, simple 

 posterodistal tooth; coxae 1-3 all small and covered by coxa 4. 



Cyphocaris 



Article 2 of pereopod 3 not deeply indentured, only coxae 1-2 reduced and 



covered by coxae 3 or 4 10 



10. Some pereopods prehensile Paracyphocaris 



Pereopods simple 11 



11. Mandible lacking distinct molar or with conicolaminate and unridged molar. 



Cyclocaris 

 Mandible bearing triturative molar (fig. 126cc) Procyphocaris 



KEY G 



The genus "Onisimus" auct. (= Boeckosimus , new genus, herein) 

 has always been poorly defined and confusing (see Stebbing, 1906, 

 key p. 9, couplet 14). Some of its species overlap with "Pseudalibi^otus" 

 auct. ( = Onisimus as senior synonym) to which I believe they should 

 be transferred. The genus also appears in Keys J and M. 



"Onisimus" auct. comprises a series ranging from entire telson (as 

 in some species of ^'Pseudalibrotus" auct.) to slightly split (as in Key 

 J) to half split (in Paronesimus and Paratryphosites ( = Hippomedon) 

 in Key M). The proportions of articles 5 and 6 of gnathopod 1 vary 

 slightly, enough to cross couplets in Key M. 



1. Pereopod 1 formed into a subchelate grasping organ similar to a gnathopod 



(fig. 1306) Endevoura and Ensayara 



Pereopod 1 simple 2 



2. Upper lip formed into a large keel-Uke lobe usually strongly projecting in 



front of epistome (fig. 125c) 3 



Upper lip usually small, obscure, and/or scarcely projecting in front of 

 epistome (figs. 125g,n,o), or epistome and upper lip coalesced, upper lip 

 if lobate equalled in extent by lobe of epistome 11 



3. Uropod 3: inner ramus less than half as long as outer, [article 5 of male 



antenna 2 dilated (fig. 124j)] Parawaldeckia 



Uropod 3: inner ramus subequal to or more than half as long as outer, 

 [article 5 of male antenna 2 not dilated, article 4 rarely dilated] .... 4 



4. Gnathopod 1 with broadly transverse palm (fig. 129a) Koroga 



Gnathopod 1 minutely but distinctly subchelate (fig. 1296) 5 



Gnathopod 1 simple (fig. 129m) 6 



5. Article 4 of antenna 2 tumid Lysianella 



Article 4 of antenna 2 slender Paralysianopsis 



6. Article 4 of male antenna 2 dilated Lysianella 



Article 4 of male antenna 2 not dilated " 



7. Uropod 3: peduncle expanded distally into a narrow, plate-like projecting 



shelf (fig. 132i) 8 



Uropod 3: peduncle simple, subcyUndrical (fig. 132(7) .... Lysianassa ' 



8. Maxilla 1 with two kinds of spines on inner plate 9 



Maxilla 1 with one kind of spine on inner plate 10 



9. Inner ramus of uropod 2 constricted (fig. 117o) [Arugella '] 



Inner ramus of uropod 2 unconstricted [Pronannonyx '] 



10. Maxilla 2: inner plate nearly twice as broad as outer . . [Shoemakerella M 

 Maxilla 2: inner plate equal to outer in width . [Lysianopsis i] and [Aruga '] 



1 1 am amalgamating all of these genera in Lysianassa, but Pronannonyx is questionable and also retained 

 as a genus in alphabetical order. 



