71 



rable young, and through it runs a narrow intestinal tube, which ex- 

 tends from the mouth to the caudal extremity of the worm, where it 

 appears to end in a ceecal point. This intestinal tube does not, as in 

 many of the Nematoidea, present any division into oesophagus, sto- 

 mach and intestine, or at all events, the former must be extremely 

 short. It appears to be a simple tube, into which is received pro- 

 bably blood or other fluid from the tissues in which the animal is 

 lodged. Its contents are a brownish, granular material, upon the 

 real nature of which the microscope throws no light. The tube it- 

 self is formed of a delicate, transparent membrane (Fig. 13). 



Owing either to the coloured substance contained within it, or to 

 the colour of the tube itself, it can readily be distinguished on open- 

 ing any specimen of the worm in a perfect state. When deficient, it 

 has probably been drawn out, as very readily happens, on account of 

 its loose and unattached condition ; for it is not connected with the 

 parietes of the worm, at all events, for the greater part of its length, 

 as the intestine is in most of the Nematoidea, by filamentary mesen- 

 teric processes. In consequence of this unattached condition it is 

 very readily lost from detached portions of the worm, and it is pro- 

 bably in consequence of some accidental circumstance of this kind 

 that Mr. Owen has been unable to detect any digestive tube after a 

 careful examination of three individuals (Cycloped. Anat., vol. ii. p. 

 144). 



The young Filarice, as I have said, occupy the cavity of the body 

 around this intestinal tube, and are mixed with a pultaceous material, 

 sometimes agglomerated into minute irregular masses. There is no 

 vestige of any ovarian tube, or of any other viscus than that described 

 above : and the only apparent outlet for the young is the open extre- 

 mity of their parent when making its exit. It would consequently 

 appear that a rupture of the body of the parent is required for the 

 escape of the offspring. 



The young of the Filar ia are amazingly numerous ; in most in- 

 stances constituting the bulk of the contents of the animal's body. 

 But they seem to me to be less crowded towards the caudal end, at 

 which part the pultaceous material in which they are lodged predo- 

 minates. 



The young Filaria, when expelled from the body of the parent, is 

 scarcely visible to the naked eye. It consists of a rounded body, 

 constituting about |ths its length, and of an attenuated tail or caudal 

 extremity constituting the other f ths. The blunt extremity exhibits a 

 rounded oral orifice, communicating with what appears at first sight 



