DISTOMA HETEROPHYBS. 



195 



In the montli of April, 1851, Dr. Bilharz, of Cairo, discovered 

 this minute parasite in the small intestine of a boy ; and on a 

 second occasion he collected several hundred specimens under very 

 similar circumstances. The parts infested displayed a multitude 

 of reddish points, due to the presence of the dark- coloured ova 

 seen in the interior of the worms. Until recently I had not had 

 an opportunity of examining this trematode, and I am, therefore, 

 much indebted to the friendliness of Leuckart for the couple of 

 specimens which he has had the goodness to send me. The close 

 inspection of these has enabled me to follow out his own accurate 

 and extended descriptions, as well as those supplied by antecedent 



EiG. 43. — Bistoma heterophyes, Von Siebokl; drawn from a specimen supplied by Leuckart (x 60 



diam.). — Original. 



observers. Without, however, recapitulating the distinctive 

 peculiarities indicated in my account of the general charac- 

 teristics of the worm, it is necessary to draw attention to the 

 very remarkable apparatus surrounding the reproductive orifices. 

 It consists of an irregularly circular disk, measuring ijs of an inch 

 in diameter, and having a thick Hpped margin, which supports 

 seventy fish-basket-like horny ribs comparable to the claw- 

 formations seen in the genus Octobothrium. According to Bilharz 

 these ribs give off five little branches from their sides, but Leuc- 

 kart could not see them in his specimens. The latter finds the 



