14 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 75 



space from the ovary to the posterior end of the body. Egg oval, 59/a 

 long by 40/A wide, without spine. 



Cercaria furcocercous, apharyngeal, spinose. Total length 410ju,; 

 body 180/i, long by 80/x wide ; tail stem 230|U, long by 45/x wide ; f ureal 

 rami 100/x long. Eyespots present, pigmented, 8/a in diameter, lying 

 near equator of body. Oral sucker 50/* long by 47/x wide ; acetabulum 

 24/i, in diameter. Penetration glands consist of three pairs of aci- 

 dophilic cells which nearly fill the postacetabular region of body; 

 penetration gland ducts open at anterior end of acetabulum and are 

 capped by an equal number of hollow piercing spines. The germ cells 

 lie in the median line caudad of the acetabulum. Execretory system 

 pattern consists of five pairs of flame cells in the body and one pair in 

 the tail stem. 



Hosts. — Primary, mammals (white rats and mice, experimentally) ; 

 secondary, snail {Lynmaea palustris). 



Location. — Intestinal veins, portal vein, and liver. 



Distribution. — North America (United States (Boston, Massachu- 

 setts) ) . 



HETEROBILHARZIA, new genus 



Generic diagnosis. — Schistosominae : Preacetabular portion of 

 male short, subcylindrical ; posterior portion with edges inrolled, 

 forming a deep gynaecophoric canal. Suckers present. Cuticle 

 covered with small tubercles. Intestinal ceca unite caudally near 

 posterior end of body. Testes numerous, 70 to 83 in number, ar- 

 ranged in two irregular rows in posterior third of body anterior to 

 cecal union. Cirrus pouch present and containing the seminal 

 vesicle. Genital pore situated at the beginning of the gynaecophoric 

 canal and to the left of the median line. Female unknown. 



Type species. — H eterohilharzia aTnericano).^ new species. 



HETEROBILHARZIA AMERICANA, new Bpecles 



Fij,aires 33-34 



Speci-fic diagnosis. — H eterohilharziu : 



Male 10 to 14 mm. long by 3 mm. wide. Cuticle covered with 

 small tubercles. Oral sucker subterminal, 350/* to 355/* in diameter ; 

 acetabulum pedunculated, 426/* to 453/* in diameter, situated about 

 568/* caudad of oral sucker. Esophagus long and surrounded by 

 the esophageal glands; intestinal ceca sinuous and uniting about 

 500/1 to 750/t from posterior end of body ; common cecum short and 

 terminating 140/i to 150/i from posterior end of body. Testes 70 to 

 83 in number, arranged in two irregular rows between the intestinal 

 ceca in i)osterior third of body. Cirrus pouch elongated transversely, 

 210/1 to 315/t long by 70/i wide, and situated about 568/i caudad of 



