THE HAIB-W0BM8. 



171 



The second suborder, Gordiacea or hair-worms, differ in 

 their mode of development from the true Nematode worms,' 

 the embryo of Gordius being armed with oval spines, thus 



Fig. 119. — Gordi//s (tquaficus. A, ege ; B, egg undergoing segmentation of the 

 yolli ; C, eiubiyo (gaslrnla) with the primitive stomach, an infold of the outer ger- 

 minal layer of cells (ectoaerm) ; D. embiyo farther advanced ; E, larva, with the 

 three circles of spines retracted withm tlie ajsopliagus ; P, the fame stage greatly 

 enlarged to show the internal orgauy; c, middle circle of spines, the head being 

 retracted ; ?/i, muscular layei (?) ; t, beali or proboscis ; i, intestine ; a, z, embi7onaI 

 cells; /, excretory tube leading from g, the secretory glands ; oi, tesophagns; v, rec- 

 tum ; n, anus. G. the second larva, encysted m a fish— (after Villot). H, Gordius 

 va7im, end of body of male, much t-nlarged. I, Gordius aquaticus^ end of body 

 <st male, much enlarged. K, Gordius agiiaticus, natural size.— (H, I, K, drawn from 

 nature by J. S. Kingsley.) 



reminding us in this respect of Echinorhynclii, but the em- 

 bryos, larviB and adult have a well-developed alimentary 

 Banal. 



