PSEUDO-HELMINTHS. 245 



of any cup-shaped appendage formed out of a folded extension of 

 the dermal covering, described by Dr. Cobbold, and which, he 

 says, consists of " a membranous bursa, strengthened internally 

 by a series of projecting rays, intended for the purpose of fixing 

 and supporting it in the same manner as we find the whalebone 

 rods employed to distend the hood of the umbrella." 



The ova sac is tortuous and convoluted, and extends through- 

 out the length of the body. It is literally loaded with eggs in all 

 stages of development, and numbering from one to two or three 

 thousand. The egg, as first seen, is a mere globular speck of 

 protoplasm, but after fertilisation takes place the mass breaks up, 

 the nuclei enlarge, and segmentation of the whole quickly follows. 

 At the same time the egg becomes ovoid in shape, with a lid or 

 micropyle at one end, and through which the young worm emerges 

 at maturity. When first hatched, the embryo is without structure. 

 It is little more than a contractile integument, enclosing innumer- 

 able granular bodies, no distinctive or formed organs being visible. 

 Notwithstanding, it is quite equal to an active migration, and pro- 

 bably will next be met with in the body of one of the smaller 

 Pulmonata, or attached to a portion of decaying vegetable sub- 

 stance, and ultimately finding its way to a pond or stream of 

 water. Evidence is certainly wanting in confirmation of the 

 statement made that it enters the body of the common earthworm. 

 In what way it really gains access to its intermediary host remains 

 a mystery. There is, however, no doubt whatever of its extraor- 

 dinary breeding powers and great tenacity of life. 



Should a single worm enter the windpipe of one of the 

 feathered tribe, it quickly proves itself a bloodthirsty foe. I have 

 seen the trachea of a young chicken swarming with Gape-worms, 

 and I have been led to wonder how breathing was sustained and 

 life prolonged. 



I conclude with a word of warning, because I have been given 

 to understand that in some agricultural districts it is no uncom- 

 mon thing for the poor people to cook and eat poultry and game 

 dying or killed from gape-disease. The head and neck is perhaps 

 severed from the body and carelessly thrown out into the dust- 

 heap, to be pecked at and eaten, and so to infect other birds and 

 animals, a prolific source of spreading a loathsome and noxious 



New Series. Vol. I. 



1888. s 



