TEE HAIR-WORMS. 



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 spmes, thus 



Fig. 119. Gordi/ix aquatictif. A, eg<r ; B, egg undergoing segmentation of the 

 yolk ; C, embryo (gastrnla) with the primitive stomach, an infold of the outer ger- 

 minal layer of cells (ectoderm) ; D. embryo farther advanced ; E, Jurva, with the 

 three circles of spines retracted within the oesophagus; F, the same stage greatly 

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

 retracted ; in, muscular layei (?) ; t, beak or proboscis; i, intestine ; 2, 2, embryonal 

 cells; /, excretory tube leading from (/, the secretory glands; , oesophagus; v, rec- 

 tu:n ; it. anus. 6. the second larva, encysted 111 a fish (after Villot). H, Gordius 

 vaiius, end of body of male, much mlargcd. I, Gordws ttyvalUtus, end of body 

 of male, much enlarged. K, Uurdius aquaticitt, natural size. \ll t I, K, drawn from 

 nature by J. S. Kingsley.) 



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

 bryos, larvas and adult have a well-developed alimentary 

 canal. 



