Pteiygodermatites Macdonaldii. 413 



and the Pohjchceta may be arranged, as follows, in a manner 

 more illustrative of their close affinities * : — 



1. Arch^ostomata. 2. Deuterostomata. 



\ / 



Trematoda Hirudinei 



Metabdelluda Olujochceta Pohjchceta 



Rotifera Arthropoda 



While on the subject it may be advisable to again refer to 

 the circumstances under which this parasite was discovered. 



I was engaged in examining the intestinal tract of a 

 specimen of Megaderma j'rons, which had been sent to me 

 from Cape-Coast Castle by Surgeon J. J. Lamprey, A.M.D., 

 when, in the lower part of the ileum, lying spirally coiled up 

 and adhering to (not covered by) the mucous membrane of 

 the intestine, I found a small worm of a pale yellow colour 

 about half an inch in length. Its very peculiar appearance 

 when examined by the microscope showed me at once that it 

 was probably not only new to science, but that it represented 

 a new order if not a new subclass of Vermes. 



Megaderma from, the host of this remarkable worm, is a 

 species of Bat of very peculiar aspectf, which is, apparently, 

 widely distributed throughout, and restricted to, the tropical 

 parts of the Ethiopian region. It belongs to a genus whereof 

 one of the species at least is known to suck the blood of 

 smaller Bats, which it captures on the wing (see my ' Mono- 

 graph of the Asiatic Chiroptera,' p. 77) ; and as all the 

 species closely resemble one another in structure, it is exceed- 

 ingly probable that they have all much the same habits. 



Although I found insect-remains in the intestinal canal of 

 the specimen from which the above-noticed parasite was taken, 

 yet there was also mixed up with them a large quantity of 

 hair, not from its own body, but evidently (judging from the 

 microscopic structure) that of some other Bat, on which very 

 likely it had been feeding. 



That this worm is really a parasite appears to be sufficiently 

 well indicated by the circumstances under which it was found. 

 It was spirally coiled up (a position which such an animal 

 would evidently naturally assume on being immersed in strong 

 alcohol, such as its host was preserved in) ; and, although long 



* Prof. Huxley remarks (' Anatomy of the Invertebrate,/ p. 220) : — 

 " Except that the Pohjchceta are almost invariably dioecious and marine, 

 while the Oligocheeta are monoecious and inhabitants either of land or 

 fresh water, it is hard to say what absolute characters separate these two 

 groups."' 



t See pi. x. fig. 3, Cat. Chiropt. Brit. Mus. 1878. 



