MARINE AMPHIPODA IN MICRONESIA — BARNARD 507 



Key to the Females and Juveniles of Maera 



1. Pleonal segment 4 with 2 sharp dorsal carinae M. insignis 



Pleonal segment 4 smooth 2 



2. Telson with notched apices 3 



Telson with blunt apices 4 



3. Third pleonal epimeron smooth behind M. inaequipes 



Third pleonal epimeron serrate behind M. inaequipes serratus 



4. Gnathopod 2, palm oblique M. othonopsis 



Gnathopod 2, palm transverse 5 



5. Adult males with 3 palmar teeth on gnathopod 2, young males, females and 



juveniles having smooth palms, with short defining tooth . M. quadrimana 

 Adult males with one blunt palmer tooth on gnathopod 2, young 

 males, females and juveniles having smooth palms, with long de- 

 fining tooth M. pacifica 



Maera hamigera Haswell 



Figure 16 



Moera [sic] hamigera Haswell, 1879b, p. 333, pi. 21, fig. 1; 1882, pp. 254-255. 



Mcgamoera suensis var., Haswell, 1885, p. 103, pi. 15, figs. 1-4. 



Maera hamigera.— Stehh'mg, 1906, p. 437.— Walker, 1909, p. 335.— Stebbing, 



1910b, pp. 600-601, 642.— K. H. Barnard, 1916, pp. 196-197, pi. 27, figs. 



11-12.— Chilton, 1921, p. 73. 



Diagnosis: No segments dorsally dentate; posterior edge of third 

 pleonal epimeron serrate, lower edge smooth; uropod 3 extending 

 much beyond uropods 1 and 2; palm of male gnathopod 2 distinct 

 from hindedge of article 6; apices of telson notched; base of article 7 

 of male gnathopod 2 strongly curved. 



Description: Eyes rather large, subreniform, ommatidia not 

 closely packed; article 6 of one male gnathopod 2 (figure 16^) rather 

 slender but very massive, palm nearly transverse but short, defined 

 by a strong tooth bearing a large spine, palm with 2 or 3 teeth; other 

 male second gnathopod (figure 16;) (usually the left one) very small, 

 of similar shape but palm lacking defining tooth and bearing several 

 large spines, article 7 not strongly curved at base; gerontic females 

 having gnathopods similar to males (figures 16a, /); other adult 

 females having both second gnathopods like the small one of gerontic 

 females (figure 16e); smaller but still adult females having both 

 second gnathopods small but the palm scarcely distinct from the 

 hindmargin of article 6 (figure 16m); finally an aberrant form was 

 found (figure IQi) havmg article 6 of gnathopod 2 stouter, the palm 

 formed into about 7 small even teeth, and the finger swollen near its 

 apex (see K. H. Barnard, 1916). 



Thus there are five principal forms of this species in these collections. 



Remarks: In light of the variability seen in this species and in 

 my initial difficulty in identifying females of this species until males 

 came to light, it is necessary to explore its relationship to such species 



768-792 — 65 4 



