ART. 18 THE TREMATODE FAMILY SCHISTOSOMIDAE PRICE 27 



Hosts. — Primary, birds {Anas platyrhynchos {^A. hoschas fera), 

 A. platyrhynchos domestica^ Querquedvla querquedvla {=Anas quer- 

 quedula), Nettion crecca {=Anas crecca) Daflla acuta {^A7ias 

 acuta), Fuligula fuUgula {=Nyroca fuligula, =Fuligula cristata), 

 Ardea cinerea, Nyroca leucophthalvia {=Fidigula leucophthalma) 

 and Cygnus olor) ; secondary, unknown. 



Location. — Abdominal blood vessels. 



Distribution. — Europe (Poland and Russia) and North America 

 (United States National Zoological Park, Washington, D. C). 



This species is represented in the Helminthological Collection of 

 the United States National Museum by a single male specimen. No. 

 17432, collected October 8, 1907, by Dr. M. C. Hall, from a swan, 

 Cygnus olor, which died in the National Zoological Park. This speci- 

 men is 3.4 mm. long by 300;li w^ide. The oral sucker is 130/a in diam- 

 eter; the acetabulum is pedunculated, 182/x in diameter, and situated 

 600/x caudad of oral sucker. Such other characters as can be ascer- 

 tained correspond so closely to those of B. polonica that there appears 

 to be no doubt as to its specific identity. 



BILHARZIELLA YOKOGAWAI Oiso, 1927 

 Figures 61-64 



Speoi'fic diagnosis. — BilharzielJa : 



Male flat, 2.3 mm. long by 96/x wade ; sides of body parallel, poste- 

 rior extremity truncate. Gynaecophoric canal short, extending from 

 immediately caudad of acetabulum to level of cecal union (accord- 

 ing to Oiso's figure). Oral sucker subterminal; acetabulum situated 

 about 300ja caudad of oral sucker. Esophagus about 250/a long: 

 intestinal ceca unite about 500|u. from anterior end of body ; common 

 cecum sinuous and terminating about 75ju, from posterior extremity of 

 body. Testes oval, 50 to 70 in number, situated on each side of the 

 common cecum; seminal vesicle large and irregular in outline, and 

 situated between the cecal branches. 



Female very slender, 3.4 to 4 mm. long by 65/li wide. Egg spindle- 

 shaped, 226ju long by 62//, wide, and containing a well-developed mi- 

 racidium. 



Cerceria furcocercous, pharj-ngeal (?), spinose. Body cylindrical 

 in shape, 262/x long by 64/1 wide ; tail stem 363)u, long by 39/Lt wide ; f ur- 

 eal rami 258/i, long by 19)u, wide. Eyespots present, situated about 

 100/x from anterior end of body. Acetabulum comparatively large 

 and well developed, and situated 235|it from anterior end of body. 

 Pharynx present (?). Penetration glands consist of three pairs of 

 large cells, the ducts of which open at anterior edge of oral sucker 

 and are capped by an equal number of piercing spines. Germ cells 

 lie in median line caudad of acetabulum. Excretory system pattern 

 consists of seven pairs of flame cells in body and one pair in tail stem. 



