NO. 14 manter: digenetic trematodes of fishes 373 



region. These are tentatively considered as C. tropicum. Agreement is 

 fairly complete (even to the exact distribution of the vitellaria), but 

 whether an anus was lacking or not was not certain. Apparently there was 

 no anus, and these specimens fit the above description in all essentials. The 

 posttesticular portion of the body seemed longer and more flat. 



Opecoelina pacifica, new species 

 (Plate 38, figs. 46, 47) 



Host: Paralabrax species (?) 

 Location : Intestine and ceca 

 Locality: Albemarle Island, Galapagos 

 Number: 15 from a single host 



SPECIFIC DIAGNOSIS OF OPECOELINA PACIFICA 



Body smooth, flattened, elongated, tapering to a rounded point at each 

 end, 1.404 to 2.130 in length, 0.607 to 0.945 in width, widest near ace- 

 tabulum. Oral sucker 0.157 to 0.217 in transverse diameter; acetabulum 

 0.330 to 0.465 in transverse diameter, without papillae; sucker ratio ap- 

 proximately 1 :2. Pharynx 0.082 to 0.112 by 0.067 to 0.087; esophagus 

 about same length as pharynx; intestinal bifurcation about midway be- 

 tween suckers ; rectum short ; anus terminal or subterminal, immediately 

 ventral to excretory pore. Genital pore well to the left (halfway or more 

 toward the left side of the body), varying from a level opposite base of 

 esophagus to opposite base of pharynx. Testes tandem, close together, in 

 posterior half of body, ovoid, slightly wider than long, smooth or (more 

 often) slightly lobed, a median indentation being common. Cirrus sac 

 well developed with a long slender cirrus portion which widens abruptly 

 to form a swollen posterior portion containing a sinuous, narrow, tubular 

 internal seminal vesicle and prostatic cells (fig. 47). Cirrus often pro- 

 truded. Posterior portion of cirrus sac overlapping acetabulum at least 

 slightly, usually about to its middle, sometimes to its posterior edge. Ex- 

 ternal seminal vesicle a wide tube, bent once near its middle ; its anterior 

 part extending diagonally to the left, its posterior part extending diago- 

 nally to the right ; extending posteriorly to level of ovary or perhaps only 

 halfway from acetabulum to ovary; connected to cirrus sac by a slender, 

 almost straight, somewhat sinuous tube. 



Ovary 3- or 4-lobed, immediately pretesticular. Uterus, Mehlis' 

 gland, yolk reservoir, Laurer's canal, and seminal receptacle preovarian. 



