\ I. KM ES. 



67 



common Round-Worms living parasitically in man (.lsr„r/s, Stron- 

 gylus, Trichocephalus) belong to this Order. Sometimes they an 

 parasitic in their early stages and later live a free life— such are 



Fig. 47. 



Fisr. K 



Fig. t9. 



m 



J- 



:/, 



/ 



>^ 



Fig. 47. Diagram of the structure of a Turbellarian : ikj, nerve- (cerebral) 



ganglia; nb, nerve-branches; yg } yolk-glands; (, testis; o, ovaj 



ov, ovary ; c, cirrus ; m, rooutli ; ph, pharynx. 

 Fig. 48. Diagram of a Nemertine : b, brain; tn, mouth; n, renal organs ; 



id, diverticula of intestine; y, gonads; sn, side nerve-trunk; 



pr, proboscis in its dorsal sheath. 

 Fig. 49. Diagram of the structure of a Nematoid : tn, mouth ; ph, pharynx : 



a, anus ; o, orifice of genital tube. 



Gordins and Mermis. A specimen of a Mantid is exhibited from 

 which half the body of the infesting Gurdius has already protruded 

 (fig. 50) . One of the most remarkable Gordii is the great elongated 

 G.fulgur, or " Lightning Snake/' from Celebes. Another very large 



