^fo. 6 gilbert: three new trematodes 97 



proximately five long filaments, about 133 /x in length, extend from 

 each pole of the egg. The excretory pore is found on the median 

 dorsal surface near the posterior end of the body. The excretory 

 vesicle is Y-shaped, forking near the shell gland. The crura extend 

 to the region of the esophagus where they end blindly. Blunt, volumi- 

 nous branches are present mostly on the outer margins of the limbs. 



GENERIC DIAGNOSIS OF MYOSACCUS 



Medium sized Pronocephalids; body smooth, truncated, muscula- 

 ture weak; collar complete. Ventral anterior depression present. Oral 

 sucker subterminal; esophagus simple; intestinal ceca voluminous 

 with short blind outpocketings. Genital pores separate, near left 

 body edge. Testes opposite, lobed, in posterior end; seminal vesicle 

 narrow, coiled anteriorly; cirrus sac short, divided into larger, very 

 muscular prostatic region, and smaller cirrus region. Ovary pretes- 

 tlcular, to right of mid-line. Uterine coils intercecal. Vitellaria extra- 

 cecal, from anterior level of testes to posterior level of seminal vesi- 

 cle. Eggs with many long filaments. Excretory vesicle Y-shaped with 

 many secondary branches on crura. Crura not uniting anteriorly. 

 Parasitic In Intestine of marine iguana, Amblyrhynchus cristatus. 

 Type species: Myosaccus amblyrhynchi, 



SPECIFIC DIAGNOSIS OF MYOSACCUS AMBLYRHYNCHI 



(Measurements in mm.) 



Body measuring 3.270 to 4.665 by 1.455 to 1.776. Anterior end 

 with weak muscular collar complete. Short ventral depression pres- 

 ent. Body rounded anteriorly, and bluntly rounded posteriorly with 

 terminal papillae present. Oral sucker subterminal and ventral, 

 slightly wider than long. Esophagus short, simple. Ceca voluminous, 

 to near posterior end, bowing towards median line In anterior fifth, 

 and between testes, short outpocketings present, no branches. Geni- 

 tal pores separate but close together near left body edge, one fourth 

 from anterior end. Testes distinctly lobed, directly opposite each 

 other near posterior end. Seminal vesicle narrow, colled free in paren- 

 chyma from level of genital pores to level of second or third uterine 

 coil. Cirrus sac divided, large portion containing narrow spindle- 

 shaped prostate surrounded by wide bundles of longitudinal muscles; 

 smaller portion containing small, stout cirrus with few longitudinal 



