NO. 3574 COPEPOD CRUSTACEANS — LEWIS 21 



unknown nature; maxillules, maxillae, and maxillipeds present in late 

 stages of development but absent in adult. Four pairs of thoracic 

 legs present although poorly developed; first 2 pairs in close proximity 

 on anterior ventral surface of trunk, third and fourth pairs removed 

 variable distance behind second pair. First 2 pairs biramous, third 

 pair typically uniramous, fourth pair probably always uniramous. 

 Remarks. — The third and fourth thoracic legs are described as 

 uniramous in the genus Pennella (Wilson, 1917; Leigh-Sharpe, 1928; 

 Yamaguti, 1963). The third leg of one of the species here described is 

 biramous. The difference may be interspecific in nature although 

 the rami of any of the thoracic legs of the adult female are brittle and 

 easily broken. 



Pennella histiophori? Thomson, 1889 



Figures 8, 9 



Pennella histiophori Thomson, 1889, p. 368, pi. 38, fig. 2. — Bassett-Smith, 1899, p. 



483.— Wilson, 1917, p. 113 (key).— Yamaguti, 1963, p. 208. 

 Pennella zeylanical Kirtisinghe, 1932, p. 137, figs. 1-5. 

 Pennella instructa? Kirtisinghe, 1964, p. 110, fig. 153. 



Hosts and distribution. — 2 host records: 



Material. — One complete, ovigerous female, 1 nonovigerous female 

 without cephalothoracic papiUae, and 1 incomplete female (trunk and part 

 of neck missing), in addition to part of larval exuvium, collected by D. 

 W. Strasburg from external siuface of Makaira audax (PhHippi) at 

 9°34'S, 136°45'W (USNM 112871). 



Remarks. — Although the host was collected far from the Hawaiian 

 Islands, the wide distribution of the host and its common occm-rence 

 around Hawaii suggested the inclusion of the copepod in this treatise. 



Measurements. — (In mm) 2 females: 



Total length (1 specimen) 



Length of cephalothorax, excluding papillae 



Width of cephalothorax 



Length of neck 



Width of neck 



Length of trunk 



Width of trunk 



Approximate length of abdominal plumosities 



Length of attachment horns 



Length of egg string (1 string) 178 



Description. — Female: Cephalothorax (figs. 8a, b) presumably 

 consisting of cephalon and fu'st thoracic segment although maxillipeds 



