.'00 



CCELHELMIXTIIES 



Tvlttu'hus Irilu'i and Hdcrodcra scJiachli, the first doing groat damage to wheat, 

 the second lo turnips in Europe. T. Jiwislatri.x attacks rye aiici hyacinths. 



Famih" 2. Asc.\rid.i:. ]\louth with three lips; males with two spicuh's. Xii- 

 merous species in lower \"ertebrates. Ascjris huiihricoidcs.'^ the round worm of 

 man (fig. 240^ inhabits the small intestine, often in enormous numbers. The 

 females are about 5-0 inches, the males 4 inches in length. .\ female contains 

 about 60,000,000 eggs Shortly after fertilization the eggs ]iass out with the 

 fxces, but develop! without intermediate host if, iu the course of two or diree 



Fig 



240.- 



-Dorsal, end, and \'entral \'iews of head and hiiuier end of male Ascaris 

 luinbricoidts i,from Hatsclick.) 



months, when the embryo is formed, thev are taken into the human 

 intestine. 1 he development c)f the piinworm, Oxxtiris t'crw/cK/j/'/.s',* is some- 

 what similar except that the embryos are developed in the egg at the litne of 

 ovifiosition, and hence after a shorter stay outsicie the bodv are capiable of in- 

 fection. The white worm, not half an inch long, lives in the rectum, especially 

 of children, and causes intolerable itching. Asioris /«v.\7ii.v* occurs in dogs 

 and cats (occasionally in man). .1. iiu-i^alocrpluhf'^ (a fa\-orite animal for 

 cytological researches) ami Oxyiiris Ci/ui in the horse, do little harm, Hiicrjkis 



iiiiiciilosa often destroys whole flocks of piigeons. Family 



Strongylid.e. 



Fig. 24;.- 

 (//, lower teetl 

 tral teeth. 



.VnU-rior tinl of hook wovi.i, . I.,^ .m.,,/,.,„„ „i,uu, ,f,il<- vafler Fooss'). 

 g. lateral gland; in, oral capsule; />, dorsal looth; o, a-sophagus; ■:■, ven- 



These are readily recognized by the bursa of the male, a broadening of the 

 hinder end of the body by two wing like jn-ocesses, which contains two spicula. 

 Frec;iuent but not constant is a widened capsule surrounded by papilke at the 

 mouth. Slransyliis'-- in domestic animals. Syii(;aiiiiis Irailirdlfs.'^ half to three 

 quarters of an inch in length, the male and female always in pairs, cause the disease 

 known as 'gapes' iu fowl. Aiiky!oslflmuiii (Doiiniiiiis) iliiojciiiilc* (fig. 247), 

 about two fifths of an inch in length, lives in the small intestine of man, causing 

 severe loss of blood. The eggs develop in moist earth, and hence people who 



