PARASITIC FLATWORMS 

 yg (74) In each proglottid normally less than three testes. 



443 



80 



80(81) Two testes in each proglottid -O/Wc///^ Clerc 1903. 



Rostellum with single crown of ten hooks having long dorsal and short ventral roots or 

 exceptionally very short dorsal root and ventral root nearly as lung as the hladc. Entire 

 surface of suckers may be armed with minute spines. Inner longitudinal muscle layer con- 

 sisting of 8 bundles, 4 dorsal and 4 ventral. Two testes in each proglottid. Ovary and vitel 

 larium always median. Adults in birds. 



Four or more species in European water birds. Most of the host species occur in North 

 America. D. acuminata and D. americana were both collected by Ransom from the coot in 

 Nebraska. 



Fig. 749. Diorchis acuminata, a. Hook from rostellum; sexually mature scRmcnt; cp, cirrus- 

 pouch; ov, ovary; t, testis; ves sent, seminal vesicle; yg, yolk gland; magnified, (.-^fter Ransom.) 



Fig. 750. Diorchis americana. a. Hook from rostellum; magnified; se.xually mature segment at 

 high focus to show male organs, dorsal view; magnified; cp, cirrus-pouch; ov, ovar>-; /, testes; vts sem, 



seminal vesicle; yp, yolk gland; magnified. (After Ransom.) 



81 (80) One testis in each proglottid \ploparaksis Clerc 1Q03. 



Fig. 751. Aploparaksis filum. Transverse section 

 of proglottid, female reproductive organs not shown; 

 X 3,6. (After Clerc.) Hook from rostellum, X 75°- 

 (After Krabbe.) 



Strobila small and slender. Rostellum 

 armed with a single crown of lo hooks, with 

 ventral root as long or nearly a.s long as 

 blade. Suckers unarmed. One testis dors;il. 

 Seminal vesicle large. Ovary and vitcUa- 

 rium always median. .Vdults in birds. 



Type species. 

 Aploparaksis Jil urn (Goczc) 17S2. 



.V dozen species described from avian 

 hosts both terrestrial and aquatic: nearly 

 all of the species arc found in North .\mcri- 

 can host s]K*cies. 



82 (71) At least six testes normally in each proglottid 83 



