350 DR. T. S. COBBOLD, FURTHER OBSERVATIONS ON ENTOZOA. 



is comparatively narrow and tortuous at the upper half, where it passes between, and 

 apparently contributes to separate, the two well-developed and irregularly oval-shaped 

 testes. The inferior half is much broader, and is occupied by numerous glittering cor- 

 puscles, which are especially numerous at the lower end. The character of these particles 

 has already been accurately described by Wedl, Wagner, and others ; but I did not observe 

 any of them connected together in the form of cellular masses, such as Claparede has 

 described as occurring in the excretory ducts of Solostomata. In connexion with the 

 reproductive system, I may notice the circumstance of a pair of these flukes being found 

 sexually united, as represented in fig. 2 ; an observation so rare, that it has, I believe, led 

 some to infer that the hermaphroditic flukes were capable of self-impregnation. Even 

 Bilharz's discovery of a trematode specially furnished with a gynsecophoric canal, afforded 

 no direct proof of a true sexual function in the androgynous Distomata, because in his 

 aberrant form — as obtains also in a few others — the sexes are separate. Many thousands 

 of flukes must have now passed under my examination, and yet this is the first instance 

 in which I have observed a true sexual union ; moreover, I am not acquainted with any 

 similar observation on record, in so far as it affects the truly hermaphroditic species. In 

 the instance now mentioned, the opposed suckers were so firmly adherent that it was 

 found impossible to detach the animals without In'eaking them up piecemeal. Lastly, I 

 may notice that the ova (/', fig. 1) contained in the u.terine folds have a longitudinal diameter 

 of only y^o of an inch. 



2. Pextastoma denticulattjm, Eudolphi. 



Pentastoma denticulatum, Rudolphi, Bremser, Wiegmann, Dujardin, Diesing and others. 

 P. tctnioides, in the young state, according to Gurlt, Kiichenmeister, and especiallj' Leuckart. See Mem. 

 in Henle and PfeifFer's Zeitsch. f. rat. Medecin, Bd. iv. p. 78, 1858. 



MemarJcs. — Although it is clear from the investigations of Schuliert and Van Beneden 

 respecting the condition and development of the embryo of 'Pentastoma, that this genus is 

 closely allied to the Acarida?, its habits are so intimately associated with those of Entozoa 

 proper, that there can be no impropriety in offering a short notice in this place. 



On the 10th of Ecbruary, 1859, I obtained numerous examples from the viscera of a 

 Bubale {Antilope Buhalis, Pallas), which had died the day previous at the Zoological 

 Society's Gardens. The greater part of these worms occupied the surface of the lungs and 

 intestines ; a considerable number, however, being enclosed in cysts beneath the pulmonary 

 pleura. Eifteen or more having l^een taken away for the purposes of microscopic exami- 

 nation and experiment, I had ample opportunity of Avatching the movements of the 

 cephalic claws whilst the animals were still living. I may here remark, that these claws 

 do not in any way resemble those of the Tape-worm family, but, in strict accordance with 

 other external features, show that the Pentastomes belong to an entirely different type. 

 Placed under the half-inch objective, with the ventral surface uppermost, the transparency 

 of the body permits a full view of the apparatus of hooks, as displayed in the accompanying 

 drawing (fig. 3). It will be here noticed that the points of the claws are directed towards 

 the observer, and not towards the longitudinal axis of the body as Kiichenmeister' s figure 

 (' Parasiten,' tab. viii. fig. 11) would lead one to suppose ; moreover, the claws ai'e placed 



