SCHISTOSOMUM JAPONICUM 



the female. A comparative study of the anatomy of the two Schisto- 

 somidae will probably show other morphological differences. Dr. 

 Catto mentions a larger vas deferens and lobular testicles in the 

 male, and a different arrangement of the yolk cells in the female. 



The dimensions given by Dr. Catto refer to a few spirit specimens, 

 and are, therefore, only relative. The male measures 9 mm. in length 

 by less than \ mm. in breadth. The slender, almost cylindrical, female- 

 is longer than the male and measures 0-113 mm. in diameter. The 

 eggs are of a yellowish-brown colour, they are oval, have neither 

 operculum nor spine, and measure from 60 to 90 yu in length by 

 30 to 50 yit in breadth. 



Professor Katsu- 

 rada's measurements 

 refer to fresh speci- 

 mens from the cat. 

 He measured eight 

 males, and found 

 'I0'43 mm. to be the 

 average length. The 

 longest male speci- 

 men measured 12 

 mm. The greatest 

 breadth of this speci- 

 men a little behind 

 the centre of the 

 body was '53 mm. 

 Only a few females 

 were found intact ; 

 they measured from 

 8 to 12 mm. The 

 greatest breadth of 

 the female was '4 mm. 



The adult worms are found in the smaller mesenteric blood- 

 vessels. Dr. Catto was unable to determine whether they occupy 

 the arteries or the veins, but believes they occur in both. However, 

 the smooth, non-tuberculated skin of Schistosomum japonicum would 

 suggest a different anatomical habitat to that of Schistosomum hcema- 

 tobium, the integument of which is beset with numerous spine- 

 bearing protuberances. Schistosomum hcematobium inhabits the venous 

 system, and its rough integument obviously enables it to adhere to 

 the inner coat of the venule during oviposition, and thus prevents 

 its being carried away by the ascending blood-stream. If Schisto- 



FIG. 117. Magnified view of fig. 116, showing ova. 



