PSEUDO-HELMINTHS, 243 



succeed in baffling the scientific acumen of the skilled Helmin- 

 thologist. 



For the reasons stated, even small and apparently isolated 

 facts are often of some importance. Now, I have lately had the 

 advantage of making myself fully acquainted with the " Gape- 

 worm " by a careful examination, and after removal by my own 

 hand of innumerable specimens from the windpipe of the young 

 pheasant, and I trust the observations I am about to offer may 

 prove acceptable to the student of natural history. I may point 

 out, first, the great disparity observed in the size of the sexes. 

 The female of the genus Sderostoma syiigaiiius measures full six- 

 eighths of an inch in length, while the male scarcely exceeds the 

 one-eighth of an inch. On detaching the female from the trachea 

 of the bird, and of which she had still a very firm hold, she was 

 of a deep-red colour, at first sight very like the smaller blood- 

 worm of the Thames, Gordiiis aquaiicus, and for which, when 

 taken out of the windpipe, she might easily have been mistaken. 

 The male worm, from its minuteness and want of colour, was at 

 first quite overlooked by me, but on a more careful search, and 

 by the aid of a pocket-lens, was at length discovered attached to 

 the upper fourth of the body of the female. The remarkable 

 tenacity of life displayed by these parasites I must not pass over 

 without notice, as on the third day after the death of the bird I 

 found, on cutting open the windpipe, the whole of the females 

 alive and vigorous, and so they remained for twenty-four hours, 

 although immersed in water and exposed to the light. 



With reference to their morphology, the integumentary cover- 

 ing of the body is uniformly smooth throughout, and about the 

 upper portion of the epidermis an irregular epithelial pigmentary 

 layer can be made out. Beneath this is the denser cutis, and 

 then a broad band of longitudinal and transverse muscular fibres, 

 which under a high power bear a striking resemblance to the 

 striped muscle of the Vertebrata. The most internal basement 

 membrane consists of a delicate mucous coat and a layer of 

 tesselated epithelium. The digestive and ccecal canal of 

 the female is seen to terminate in a sharply-pointed anal open- 

 ing, which also serves as an ovipositor. The terminal portion 

 of the male differs very considerably. It is truncated and 



