142 



ZOOLOGY 



distinct ganglia in each somite, the stomodaeal muscular bulb is 

 armed with three teeth, and the sexes are separate. 



Fig. 90. — Polygordius neapoUtanus. 



A. Transverse section of a male Poly- 

 gordius. 



1. Cuticle. 



2. Eotodermic epithelium. 



3. Muscle plates. 



4. Parietal coelomic epithelium. 



5. Visceral coelomic epithelium. 



6. Ciliated endodermal epithelium. 



7. Dorsal blood-vessel in dorsal mesen- 



tery. 



8. Ventral hlood- vessel in ventral 



mesentery. 

 The body-wall has undergone partial histological degeneration, and is ruptured in 

 two places to allow the escape of the ova (13) which crowd the coelomic space. 



Polygordius is the largest of the Archiannelids. P. 

 lacteus is 40 mm. long (Fig. 89). The longitudinal ventral 



9. Oblique muscular septum covered 

 with coelomic epithelium. 



10. The testes. 



11. Ventral nerve cord, continuous 

 with 2. 



B. A spermatozoon. 



C. Horizontal section of a mature female 

 Polygordius. 



1, 2, 3, and 6 as in A. 



12. The septa. 



13. Ova. 



