584 



TREMA TOD A 



FAMILY SCHISTOSOMIDvE Looss, 1899. 



Definition.^ — -Fascioloidea with separate sexes, and with genital 

 pore posterior to the elevated acetabulum. No pharynx. In- 

 testinal caecare unite to form a single intestine. 



Type Genus. — Schistosoma Weinland, 1858. * 



Schistosoma Weinland, 1858. 



Synonyms. — GyncBcophorus Diesing, 1858; Bilharzia Cobbold, 

 1859; Thecosoma Moquin-Tandon, i860. 



Definition. — Schistosolnidae with long filiform females and shorter 

 males, with body considerably widened behind the acetabulum. In 

 this part the lateral walls can curve ventrally to form an almost 

 closed canalis gyncecophorus, within which the female is enclosed. 

 No cirrus pouch. No pharynx. No Laurer's canal. Eggs with 

 spines and no lids. Miracidia ciliated with large glandular cells 

 discharging anteriorly beside gastric sac. Development in various 

 snails. Cercariae with forked tails and no eye spots. Enter 

 vertebrate hosts through skin or mucosa, and pass into blood- 

 vessels. 



Classification. — -The species known to occur in man may be 

 recognized as follows (5. magna Cobbold, 1852, found in a monkey — 

 Cercocebus fuliginosus — ^is represented to-day by only a piece of a 

 male, which Leiper says cannot be recognized as belon|ing to a 

 human species) : — 



A. Cuticle with spines: — 



I . Male, four to five large testes ; female, ovary posteriorly 

 situate. Eggs, terminal spined. Development in 

 subgenera and species oi Bullinus — Hcematohium. 

 1 1 . Male, eight small testes ; female, ovary anteriorly situate . 

 Eggs, lateral spined. Development in species of 

 Planothis — Mansoni. 



B. Cuticle nearly smooth, only a few spines seen in fresh con- 



dition along margin of canal. 

 Male, six to eight testes; female, ovary almost in middle 

 of body. Eggs with small lateral spines or thickenings. 

 Development in species of Blanfordia — faponicuni. 



Schistosoma haematobium Bilharz, 1852. 



Synonyms,— Distomum hcBmatohium Bilharz, 1852; D. capense 

 Harley, 1S64', Bilharzia hcBmatobia Cobbold, 1859. 



Definition. — Schistosoma with spiny cuticle. Males with four to 

 five large testes and with intestinal caeca uniting late to form a 

 short single intestine. Females with ovary in the posterior half of 

 the body. Uterus very long, with many terminal spined eggs. 

 Vitellaria in posterior fourth of the body. Development of cercarige 

 in subgenera and species oi Bullinus. 



History. — Schistosoma hcBmatohium was discovered in the portal 

 vein of a man in 1851 by Bilharz in Cairo, and later by Harley in 



