TREMATODES 



175 



M. floridana Pratt (Fig. 282). Body 1.3 mm. long: aiul .58 mm. wide; 

 oral sucker present; intestinal branches joined at binder end and pro- 

 longed in a median coecum : on tbe gills ><rs-r^"N^ - i 

 of Myliohatis freminvillei. 



Family 3. POLYSTOMIDAE. 



Body flat and broad, with a more 

 or less distinct disc or region at the 

 hinder end bearing suckers, usually 

 paired, the number of which may vary 

 from 2 to 120, and also in most cases 

 hooks; anterior suckers either present 

 or not: on gills of fishes and in the 

 mouth, nose, and urinary bladder of 

 amphibians and reptiles; about 21 

 genera and 3 subfamilies. 



Key to the subfamilies of Poly- 

 stomidae : 



«! Anterior suckers absent ; either 2 or 6 

 posterior suckers. 1. Polystominae 



aj Anterior suckers present. 



&i Posterior suckers 4 to 8 2. Octocotylinae 



62 Posterior suckers very numerous ^- Microcotylinae 



mm"^- im^mm '^^mm 



■ ^^^<<i^^^:^ ^^^^?^v^^'ifei 'S^";";'^"^^^^ 



Fig. 281- 



-Epihdella humpusi 

 (Linton). 

 References as in Fig. 278. 



Subfamily 1. POLYSTOMINAE. 



Posterior sucking disc distinctly set off and with 

 2 or 6 large suckers arranged in pairs and also 2 

 or more large hooks; paired anterior suckers absent: 

 about 5 genera. 



1. PoLYSTOMA Zeder. Body without anterior 

 and with 3 pairs of posterior suckers ; vagina paired 

 with an opening on either margin of the anterior 

 portion of the body: on the gills of frog tadpoles 

 as larvae, and in the urinary bladder of amphibians 

 and in the mouth, nose, and urinary bladder of 

 turtles as adults; 6 species, 3 in America. 



P. oblongum R. R. Wright. Disc attached at 

 its anterior end; intestine with no side branches; 

 body elliptical; cirrus with 16 spines, alternately 

 large and small; length 2.5 mm.; width 1 mm.: in urinary bladder of 

 musk, painted, and snapping turtles. 



Fig. 282 



Monocoti/le floridana 



(Pratt). 



References 



as in Fig. 278. 



