NO. 14 MANTER : DIGENETIC TREMATODES OF FISHES 353 



mens from Angelichthys (fig, 24) were all greatly extended. The exces- 

 sive extension of the forebody probably explains differences of these trem- 

 atodes. A striking similarity between the trematodes from the 2 hosts is 

 seen in the peculiar excretory system with the long vesicle extending me- 

 dian to the right intestinal cecum, bending ventrally anterior to the geni- 

 tal sinus to cross the intestinal bifurcation ventrally and reaching to the 

 pharynx or even to midphaiynx level. The excretory vesicle of all species 

 of Opechona is supposedly a simple tube. The occurrence of another small 

 longitudinal branch just median to the left cecum is thus unexpected. Its 

 connection to the main vesicle is not clear. 



Lepidapedon hancocki, new species 

 (Plate 35, fig. 26) 



Hosts: Mycteroperca olfax (Jenyns) (type host) 

 Mycteroperca xenarcha Jordan 

 A large, spotted grouper; unidentified 



Location: Intestine 



Locality: All hosts were from the Galapagos Islands 

 (Albemarle and James islands) 



Number: From one to 15 in a host 



SPECIFIC DIAGNOSIS OF LEPIDAPEDON HANCOCKI 

 Body flattened, spined, elongated, widest in its middle third, taper- 

 ing anteriorly, more bluntly rounded posteriorly; length 1.458 to 3.997; 

 width 0.553 to 0.948. Oral sucker 0.157 to 0.255 in diameter; acetab- 

 ulum 0.127 to 0.187 in diameter; sucker ratio about 4:3; forebody Yz 

 to ^ body length. Prepharynx short; phaiynx 0.090 to 0.136 long by 

 0.052 to 0.082 wide; esophagus muscular, slightly longer than pharynx; 

 intestinal bifurcation about midway between the suckers; ceca narrow, 

 ending blindly near posterior end of body. Genital pore sinistral, some 

 distance anterior to acetabulum, not far from left cecum. Testes smooth, 

 tandem, close together, wider than long, in posterior third of body. 

 Posttesticular space 0.157 to 0.300. Cirrus sac clavate, extending almost 

 halfway to ovary, with elongate seminal vesicle extending about half its 

 length, large ovoid prostatic vesicle, a short and wide pars prostatica, 

 few prostatic cells, and a muscular cirrus. External seminal vesicle a 

 large, wide sinuous tube surrounded by a mass of gland cells, extending 

 almost to ovary. Ovaiy ovoid, wider than long, smooth, a short distance 

 anterior to testes; Mehlis' gland just anterior to ovary; flask-shaped 

 seminal receptacle originating just anterior to ovary, extending along 



