TMB EAIB-WORMS. 



171 



The second siiborder, Gnrdiacca or hair-worms, differ in 

 their mode of development from the true Nematode worms, 

 the embryo of Gordins being armed with oval spnies, thus 



Pig. 119. — Gonlriis uqvatvim. A, egg ; B, egg undergoing segmentation of the 

 yolk ; C, embryo (gaslnila) with the primitive stomacli. an infold ot thu outer ger- 

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

 three circley of spines retracted wjthm the ai^ophagus ; F, the same stage greatly 

 enlarged to show tlic internal orgaii(> ; c, middle circle of spines, the head being 

 retracted ; ?/i, innscular layei (?) ; t, beak or jiroboacis; i, intestine ; 2, z, embryonal 

 cells; /, excretory tube leading from ri, the secretory glands; t«, oesophagus; v, rec- 

 tum; 7(. anus. 6. the second larva, encysted in a fish~(after Villot). H, Oordivs 

 vaHus, end of body of male, much enlarged, i, Gordius aqualkas, end of body 

 of male, much enlarged. K, Oordiit6 uqaaiicits, natural siiie. — (H, I, K, drawn from 

 nature by J. S, Kingslcy.) 



reminding us in this respect of Echinorhynchl, bnt tlie em- 

 bryos, larvae and adult have a well-developed alimentary 

 canal. 



