198 ENTOZOA. 



admits lias tlie priority. Though it is of little consequence 

 which name be retained, the genus itself is one of remarkable 

 interest, not merely in a structural point of view, but also from 

 its prevalence on the borders of the Nile, and also, according to 

 Dr. John Harley, in South Africa and the Mauritius. The first 

 specimens were discovered by Dr. Bilharz, of Cairo, in the portal 

 system of blood-vessels ; and others were subsequently observed 

 by him, Griesinger, E-einhard, and Lautner in the veins of the 

 mesentery, bladder, and other parts, giving rise to a formidable 

 and very common disease. This malady is likewise endemic at 

 the Cape of Good Hope. On the 4th of December, 1857, I 

 discovered a bisexual fluke of this kind in the portal vein of a 

 Sooty Monkey (Gercopitheciis) which had died at the Zoological 

 Society's menagerie ; and, at the time, as well as for a considerable 

 period since, I believed it to be a species distinct from the worm 

 described by Bilharz. It was accordingly named Bilharzia magna. 

 However, whilst I still retain the generic title which was then 

 adopted, I do not now scruple to abandon the specific name, 

 because I am fully inclined to agree with Leuckart that the two 

 forms are identical. The disparity of size which then appeared to 

 be a bar to their identity, does not in reality exist, since Leuckart 

 has shown that some of the specimens derived from human sources 

 were as large as the one which I found in the monkey. In any case 

 the occurrence of this curious genus in the blood-vessels of man and 

 monkeys is liighly suggestive. It forms an interesting little 

 circumstance, admirably suited to the taste of those who are on 

 the look-out for affinities of habit between bimana and quadru- 

 mana. The Gercopithecus fuliginosus is an Afi:'ican monkey, and, 

 no doubt, in its native haunts it procures the larvaa of Bllharda 

 from the same or from similar sources as those from whence our 

 brethren in Egypt procure their larvae. Animals lower in the scale 

 do not appear to be liable to attacks from this strangely organized 

 genus of flukes, and, as yet, we are uninformed as to the liosts which 

 entertain it in its larval condition. 



