INTEKiXAL ANATOMY. 



8i 



e.o 



In the posterior chamber there are four pairs of much 

 larger nephridia, which are similarly joined together by a 

 prominent longitudinal duct from which short processes 

 corresponding in number to the nephridia lead to the 

 external apertures. The 

 duct itself ends blindly at 

 both ends, but is prolonged 

 posteriorly far beyond the 

 region of the nephridia 

 (Fig. 40). 



The presence of this 

 longitudinal duct in these 

 worms is a very remark- 

 able circumstance, but it is 

 undoubtedly an expression 

 of the same phenomenon as 

 the anastomoses between 

 successive nephridia which 

 have been described by 

 EisiG for the Capitellidae, 

 as well as the complicated 

 series of anastomoses which 

 convert the entire nephri- 

 dial system into a marvel- 

 lous network of tubules dis- 

 covered by A. G. Bourne 

 in the marine leech, Pon- 



Fig. 40. — Schematic lateral view of 

 anterior end of Lanice couchlk^a to show 

 the nephridia. (After Eduard Meyfr 

 from Hatschek's Lehrbi/ck's der 7.ooIos^it\^ 



The ventral side of the body is to the 

 left of the fit^ure. d. Longitudinal ducts of 

 the nephridia. e.o. Position of external 

 openings, f. Nephridial funnel ( — coelomic 

 opening of nephridium). m. Position of 



mouth; hounded bv two prominent lateral 

 tobdella, and by BeDDARD lobes, and fringed by a great number of 



" feelers," which are cut short in the figure. 

 m the curious earthworm, /. Branchial tentacles (three on each side 



PerichcEta. of the body). 



The present state of our knowledge does not admit of 

 an attempt to specify the particular type of nephridial 

 system from which that of the Annelids, on the one hand, 



