MARINE AMPHIPODA IN MICRONESIA — BARNARD 497 



Elasmopus levis Smith is the species considered in couplet 8 and 

 not the homonym E. levis K. H. Barnard (1916) which has been 

 renamed E. vagans by K. H. Barnard (1940). 



Elasmopus chevreuxi Cecchini (1928) : both Schellenberg (1938a) 

 and Ruffo (1959) refer this to E. brasiliensis. 



References to all species may be consulted in J. L. Barnard's index 

 (1958) except: 



E. rapax m.utatus and E. holgurus: both described by J. L. 

 Barnard (1962b). 



The following species should be transferred to Maera Leach: Elas- 

 mopus latibrachium Walker (1905), E. smirnovi Bulycheva (1952), and 

 E. sokotrae Walker and Scott (1903). 



Key to Males of Elasmopus 



1. Some bod}' segments dorsally dentate 2 



No body segments dorsaUy dentate 5 



2. Four segments dorsally dentate 3 



One segment dorsally dentate 4 



3. Gnathopod 2, palm very oblique E. diemenensis 



Gnathopod 2, palm nearly transverse E. siiensis 



4. Article 2 of pereopod 5 alate, proximally widened E. neglectus 



Article 2 of pereopod 5 normally oval E. japonicus 



5. Gnathopod 2, palm transverse E. dubius 



Gnathopod 2, palm oblique 6 



6. Right and left second gnathopods differing in structure . . . . E. bollonsi 

 Right and left second gnathopods alike in structure 7 



7. Palm of gnathopod 2 with a large cuplike medial hollow 8 



Palm of gnathopod 2 lacking medial cuplilce hollow 9 



8. Medial apex of each telsonic lobe rounded E. pocillinianus 



Medial apex of each telsonic lobe sharp E. levis 



9. Palm of gnathopod 2 lacking major teeth, tubercles or processes .... 10 

 Palm of gnathopod 2 bearing teeth, tubercles or with a blunt process near 



finger hinge 15 



10. Palm of gnathopod 2 distinct and defined either b}' a stout articulated spine 



or by a sharp palmar corner 11 



Palm of gnathopod 2 not distinctly defined 12 



11. Gnathopod 2, palm defined by a stout spine, no other stout spines 



present E. magnispinatus 



Gnathopod 2, palm defined by a sharp corner, palm and hindmargin of 

 article 6 furnished with additional spines E. steinitzi 



12. Dactylus of pereopods 1-2 with 2 nails, article 6 with a stout distal 



spine E. diplonyx 



Dactylus of pereopods 1-2 with one or no nail, article 6 lacking a stout 

 distal spine 13 



13. Gnathopod 2, part of palm minutely crenulated E. dentiferus 



Gnathopod 2, palm not minutely crenulated 14 



14. Articles 6-7 of gnathopod 2 quite elongated, article 7 sinuous . . E. gracilis 

 Articles 6-7 of gnathopod 2 not elongated, article 7 not sinuous. 



E. brasiliensis 



