352 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



Variable characters of O. pharyngodactyla include the length of the 

 prepharynx, length of the pharyngeal processes, and the sizes of the in- 

 ternal and external seminal vesicles. 



Opechona orientalis (Layman, 1930) Ward and Fillingham, 1934 



(Plate 34, figs. 24, 25) 



Synonym: Pharyngora orientalis Layman, 1930 



Hosts and Localities: Angelichthys sp., angelfish, from un- 

 known locality (taken from ship's tanks) 

 Paranthias furcifer (Cuv. and Val.) 

 from Clarion Island, Mexico 

 Small mackerel, Tagus Cove, Albemarle 

 Island, Galapagos 



Location: Intestine 



Number : 8 specimens from a single Angelichthys 

 10 specimens from 2 of 13 Paranthias 



The angelfish host was a fish which died in the tanks. These trema- 

 todes had lost body spines but otherwise were in fairly good condition, al- 

 though they were dead when collected. Their characters seem to agree 

 specifically with those of O. orientalis, a trematode previously reported by 

 Layman (1930) and by Yamaguti (1934) from Scomber japonicus, 

 Spheroides riibripes, and Engraulis japonicus from Peter the Great Bay 

 and Toyama Bay. The specimens from Angelichthys (fig. 24) give the 

 following measurements, all of which fall within the limits of O. orien- 

 talis: length 1.363 to 2.214; width 0.307 to 0.375; forebody about Yz 

 body length; oral sucker often elongate; prepharynx 0.165 to 0.285; 

 pseudoesophagus shorter than esophagus, the 2 together being subequal to 

 the prepharynx in length; sucker sizes and ratios as in O. orientalis; eggs 

 51 to 61 by 27 to 34 jx. The extent of the cirrus sac, of the vitellaria, size 

 and shape of the genital atrium correspond exactly with O. orientalis. 

 The excretoiy vesicle, undescribed for O. orientalis, extends to the phar- 

 ynx, crossing the intestinal bifurcation ventrally. A second smaller and 

 shorter branch of the vesicle extends in the left half of the body to the re- 

 gion of the base of the cirrus. 



The ten specimens from Paranthias furcifer (fig. 25) were smaller 

 (0.712 to 0.972 by 0.270 to 0.367 mm), the forebody shorter and wider, 

 the prepharynx and esophagus only about the length of the pharynx, the 

 vitellaria in each specimen reaching to the posterior edge of the acetabu- 

 lum, the ovary more compact, the testes wider than long. But the speci- 



