The above morphological descriptions are founded on worms of each species, derived from experimentally infected mice (Leiper, R. T., Brit. Med. Journ., March 18, 1916, p. 411).
Schistosoma japonicum, Katsurada, 1904.
Syn.: S. cattoi, Blanchard, 1905.
Fig. 176.—Schistosoma japonicum: anterior end with testes; posterior end with point of union of cæca. Length of worm about 10 mm. (After Katsurada.)
Male.—Eight to 19 mm., but extreme limits are 5 to 22·5 mm. Consists of a short fore-body, separated by the ventral sucker from the hind-body. The ventral sucker is stalked and somewhat larger than the oral sucker. Both suckers are larger than the corresponding ones in S. hæmatobium. Body usually smooth, but in the fresh state numerous fairly evident spines along the margin of the canal. Œsophagus: two bulbs. The junction of the gut forks more posterior than in S. hæmatobium, the median united gut stem occupying a quarter to one-fifth to one-sixth of the body length. An excretory canal runs along each side of the body, opening into the dorsal excretory pore. Testes irregularly elliptical, six to eight in number, in the anterior part of hind-body. The vasa efferentia unite into a common vas deferens which opens directly behind the ventral sucker. The seminal vesicle lies just behind this.
Fig. 177.—Schistosoma japonicum, male and female in copulâ. × 60. (After Katsurada.)