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PROCEEDINGS OF THE NATIONAL MUSEUM 



with large, irregular, heavily sclerotized projection of outer portion 

 that forms articulation surface for third segment. Third segment 

 small, proxhnal end irregular, heavily sclerotized; division between 

 terminal process and segment indistinct; setalike accessory process 

 present, distal to division between segment and terminal process. 

 First 2 thoracic leg pairs in close proximity at anterior end of neck, 

 third placed well behind second, and fourth behind thu-d; ratio of 

 proximity equals 1 (first to second leg) : 5.5 (second to third) : 5.5 (thu-d 

 to fourth) (fig. 9d). Protopodite of legs 1-segmented although appear- 

 ing 2-parted, attached to well-developed interpodal plate. First 

 thoracic leg biramous, rami 2-segmented, second leg appearmg 

 uniramous, both in adult female (fig. 9/) and larval exuvium (fig. 9j), 

 although outline of leg and presence of exopodite on adult leg and 

 endopodite on larval exuvium suggest loss of endopodite in adult 

 specimen. Third and fourth thoracic legs without distinct indication 

 of rami. Protopodite of all legs with dark brown to black pigment 

 spot m alcohol-preserved specimens. For nature and armature of 

 thoracic legs, see figures 9e-j and table 5. 



Tablk 5. — Armature of thoracic legs I-IV of the female of Pennella histiophori? 



Thomson, 1889 



Discussion. — The identification of the Hawaiian material as 

 Pennella histiophori? Thomson, 1889, as well as the inclusion of 

 the two names used by Kirtisinghe in the synonymy, is done with 

 some question. The intraspecific variation present within the mem- 

 bers of the genus, the mde distribution of many of the hosts of the 

 genus, and the relative absence of definitive descriptions leave the 



Figure 9. — Pennella histiophori? Thomson, 1889, female: a, ocular region, dorsal view 

 showing rostrum (r), antennule base (a-1), and antenna base (a-2); b, antennule, dorsal 

 view; c, antenna, dorsal view; d, pedigerous region of neck, ventral view. Right thoracic 

 legs: e, first, posterior view;/, second (endopodite missing), anterior view; g, third (ramus 

 or rami missing), posterior view; h, fourth (ramus missing), posterior view; i, distal end 

 of protopodite of fourth, posterior view. Pedigerous region of larval exuvium: ;', ventral 

 view (A = anterior). 



