512 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.2 



Nipporhynchus ornatus (Van Cleave, 1918) 

 (Plate 54, fig. 15; Plate 55, fig. 18) 



Synonymy: Echinorhynchus pristis (in part) of Linton, 1892 

 Rhadinorhynchus ornatus Van Cleave, 1918 



Rhadtnorhynchus katsuwonis Harada, 1928 

 Nipporhynchus katsuwonis (Harada, 1928) Chandler, 1934 



Hosts: Euthynnus alletteratus (Raf.), Charles Island, Galapagos, 

 January 27, 1934 



Katsuwonis pelamis (Linn.), Charles Island, Galapagos, Janu- 

 ary 30, 1934 



Euthynnus alletteratus (?) or Katsuwonis pelamis (Linn.), 

 Galapagos Islands, June 11, 1934 



Specific diagnosis. Fully mature females about 25 mm long, with 

 maximum diameter of about 0.7 mm, tapering toward either extremity 

 to a diameter of about 0.5 mm. Male about 17 mm long with a diameter 

 of about 0.6 in region of the testes. Proboscis cylindrical to clavate, 2 

 to 2.5 mm long by about 0.23 mm in diameter, often with a slight 

 swelling near anterior tip; armed with 22 to 24 longitudinal rows of 

 38 to 45 hooks each. Hooks of basal circle approximately 82 to 100 ja 

 long, without any specialized ventral crescent; on mid-ventral surface 

 of proboscis about 59 /*; on middorsal more slender; near anterior end 

 about 76 jLi long. Testes contiguous ; cement glands 4, long, tubular. 

 Lemnisci distinctly shorter than proboscis receptacle. Body spines ar- 

 ranged as a collar of scattered spines on anterior body extremity followed 

 by an unspined area and then with scattered spines, chiefly on ventral 

 surface but not extending posteriorly as far as the end of the proboscis 

 receptacle. Spines about 76 /x long. Retinacula about three fifths the 

 length of the proboscis receptacle from its posterior end. Embryos within 

 body of gravid female 59 to 69 fi long by 20 to 24 jx in diameter. 



The geographical range of this species has been greatly extended by 

 this record. Previously known only from northeastern United States, 

 the species is here recorded from Charles Island of the Galapagos group. 

 The species evidently has wide range of host relationships. The present 

 record is the first instance of description of a male of this species. 



