138 PHEASANTS FOR COVERTS AND AVIARIES. 



Spencer Cobbold, who contributed the account of its history 

 and treatment to the Linnean Society, from which the 

 following abstract is taken: 



" This parasite has been found in the trachea of the 

 following birds, namely, the turkey, domestic fowl, pheasant, 

 partridge, duck, lapwing, black stork, magpie, hooded crow, 

 green woodpecker, starling, sparrow, martin, linnet, crow, 

 rook, and swift. 



" My attention was recently directed to a small, almost 

 featherless chicken suffering from the ' gapes.' The bird 

 belonged to a brood between six and seven weeks old. The 

 healthy birds had attained considerable size, and averaged 

 9i ounces ; the infested chicken weighed only 4 ounces ; but, 

 as if to make up for its defective assimilating powers, greedily 

 devoured everything which came in its way, consuming two 

 or three times as much as any other member of the brood. 



te The female worms extracted from the trachea have an 

 average length of fths of an inch, the males scarcely 

 exceeding ^th of an inch. In both sexes the bodies are 

 tolerably uniform in breadth throughout. The mouth of 

 the female is furnished with six prominent chitinous lips 

 (Fig. 2). The male is usually found fixed by means of a 

 strong membranous sucker (Fig. 4). The eggs of Syngamus 

 are comparatively large, measuring, longitudinally, as much 

 as the l-250th of an inch (Fig. 5). Many of the ova contain 

 fully-formed embryos. By whatever mode the young make 

 their exit from the shell, it is manifest that prior to their 

 expulsion they are sufficiently developed to undertake an 

 active migration. Their next habitation may occur within 

 the body of certain insect larvae or even small land molluscs ; 

 but I think it more likely that they either enter the sub- 

 stance of vegetable matters or bury themselves in the soil 

 at a short distance from the surface." 



Since the publication of this paper, the history of the 

 gapeworm has been very carefully studied by other observers, 

 whose investigations have been recapitulated in Theobald's 



