306 



CE3T01DEA.- 



-ENTOZOA.- 



-Entozoa. 



increase in size, and at the end of eight weeks it was 

 found to have grown from the size of a pea to the length 

 of from thirty-six to 



ova are not 



worms, but 



thirty-nine inches. 



The most generally 

 known and perhaps the 

 largest of all the Tape- 

 worms, is the species 

 which inhabits the in- 

 testinal canal of man. 

 Fig. 208 is that of tlio 

 Tania crassicollis men- 

 tioned above. 



The Cystic worms, 

 formerly constituting a 

 separate ordi-F, Cesloi- 

 (lea, and now provi- 

 sionally a family, Cysti- 

 cilice, are only, as 

 mentioned above, stray 

 Tanice, which hava 

 nssnnied a vesicular 

 form and have not 

 developed genital or- 

 gans. They are the 

 produce of the micro- 

 scopic ova of the Ces- 

 toid worms belonging 

 to certain carnivorous 

 ariimals accidentally 

 introduced into the 

 bodies of rodent or 

 ruminant quadrupeds. 

 In such situations these 



Fig. 20S.— Tffinia crassicollis. 



developed into elongated, articulated Tape- 

 into Cystoid worms, the body being ternji- 

 nated by a vesicle of a 

 bottle-shape and filled 

 with fluid. They do 

 not assume their per- 

 fect form till they 

 have passed through 

 the stomach of the 

 Carnivora to which they 

 originally belonged; but 

 nevertheless while in 

 their undeveloped form 

 as Cystoid worms, they 

 produce intense sufi'er- 

 ing, serious illness, and 

 ultimately death, in the 

 poor creatures in whose 

 bodies they have taken 

 up their abode. Such 

 are the species of Cysti- 

 cercus, Cosnurus, &c. 



The history of the 

 worms called Entozoa 

 is full of interest, but 

 in a work of this soit 

 we must content our- 

 selves with merely a 

 brief sketch of the clas- 

 sification and leading 

 families and genera. 

 Enough, we trust, has 

 been said to stimulate 

 inquiry, and to aid tho 

 reader ia pursuing it. 



EXD OF CRUSTACEA, ETC. 



