TREMATODES 



177 



D. affinis (Linton). Body attenuate, spatulate; anterior portion 

 elliptical; posterior i)ortion cylindrical; posterior suckers witli long 

 stalks: length 12 to 40 mm.: in tlie mouth of the flounder. 



Subfamily 3. MICEOCOTYLINAE. 



Paired anterior suckers present; posterior disc-like region elongate 

 and bearing numerous small suckers, which may be found only on one 

 side, making the animal asymmetrical: 4 genera. 



MiCROCOTYLE van Beneden and Hesse. Posterior 

 region bearing 10 to 120 pairs of minute sessile suckers : 

 on gills of marine fishes; many species. 



M. longicauda Goto. Sucker disc more than 

 the length of the body; about 120 pairs of suckers 

 ent; 7 mm. long; 2 mm. wide: on the gills of the 

 fish; Newport. 



M. pogoniae MacCallum (Fig. 

 286). Sucker disc about a third of 

 the body ; length 12 mm. : on Pogonias 

 cromis, often very numerous. 



Family 4. GYRODACTYLIDAE. 



Minute forms occurring on the 

 gills of fresh-water and marine fishes ; 

 body minute, usually without suck- 

 ers, but with 2 to 4 retractile ten- 

 tacles at the forward end 

 and a disc at the hinder end 

 armed with numerous hooks: 

 about 9 genera. In the genus 

 Gyrodactylus a curious paedo- 



genesis often occurs. A young individual will come 

 to sexual maturity before it is born and while it is 

 still in the maternal uterus, and produce young in its 

 uterus. This last individual may also have young in 

 its uterus, and 4 generations may thus be found, one 

 inside of another. 



Gyrodactylus Nordmann. Minute, elongated 



worms with 2 short anterior projections and a posterior disc bearing 



about 16 marginal hooks and 2 large central ones; no eyes present: 



4 species. 



G. elegans Nordmann (Fig. 287). Length 1 mm.; width .2 mm.: on 



the gills and skin of the carp and other fresh-water fishes. 



Fig. 286 — Microeotyle 



pogoniae (MacCallum). 



References as in Fig. 278. 



Fig. 287 — Gpro 

 dactt/lus eleganf 

 (fromBronn). a. p. 

 anterior projec 

 tion ; p.p., phar 

 ynx. Other refer 

 ences as in Fig 

 278. 



