STUDIES ON EARTHWORMS. 93 



of a compact mass of tubules (fig. 28) ^ or rather of a single 

 very greatly folded tubule (a), the folds of which are pressed 

 close against one another, and contain parallel lumina, which 

 in some regions appear to be ciliated. From the outer side 

 of this mass arises the vesicular portion or duct (b), which is 

 irregular in diameter, bends upon itself three or four times, and 

 then passes forwards as a narrow, straight duct, lying alongside 

 the pharynx, to its external pore. The structure of this ne- 

 phridium is quite similar to the unmodified posterior ones. In 

 Urochseta Perrier describes " glandes a mucosite,'^ which 

 have the same position, and Beddard describes a modified 

 nephridium in Ac. multiporus, which opens, not to the 

 exterior, but into the buccal cavity. It seems probable that 

 all these glandular bodies in the anterior region of the body 

 may be modified nephridia. 



The vascular system consists of the usual longitudinal 

 vessels, viz. dorsal, ventral, and typhosolar trunks, together 

 with a series of lateral hearts. I could see no lateral longitu- 

 dinal (''intestino-tegumentary"^) trunks. The dorsal trunk in 

 the posterior region of the body is only slightly moniliform, 

 but as it passes forwards this condition becomes more marked, 

 especially in somites xvi to xii. In somite xi a pair of monili- 

 form lateral hearts are given ofi", and similar ones are found 

 in somites x, ix, and viii, each being smaller than that behind 

 it. In the next two anterior somites the '' commissural vessels " 

 are no longer moniliform, and are very much more delicate 

 than the posterior vessels. 



The nervous system consists of the usual cerebral ganglia, 

 which are here well marked, and lie in somite iii and a series 

 of ventral ganglia. These lie quite close together, so that the 

 intervening cord is very short (fig. 30). This is doubtless due 

 to the greatly contracted state of the worm. Three or four 

 pairs of lateral nerves are given off" from each ganglion, but 

 none from the short cord. Probably if the contraction were 

 less and the ganglia longer some of the lateral nerves would 

 appear to come off from the cord. 



Just as Urobenus has certain resemblances to Urochaeta, 



