1887.] 



NEW GENUS OF LUMBRICIDjE. 



161 



which is so well marked ia TJrochceta and in Acanthodrilus tnuKi- 

 porus, is, as it were, just commencing in Thamnodrilus. 



(2) The next fourteen pairs of nephridia (see fig. 5) open on to the 

 exterior of the body iu a line with the dorsal pair of setfe ; the most 

 anterior nephridia are rather smaller than the posterior pairs in corre- 

 sponding with the increasing width of the segments. The glandular 

 part of the nephridium is very slightly developed in comparison with 

 the extremely elongated muscular sac which communicates with the 

 exterior ; at the junction of the two regions of the nephridium, the 



Fig. 6. 



One of tbe Posterior Nej^hridia. Letteriug as in fig. 5. 



muscular duct becomes dilated and bent slightly upon itself; its 

 walls become glandular ; this portion of the gland is distinguishable 

 by its opaque white appearance. 



(3) From the 1 7th segment to the end of the body the nephridia 

 are of a somewhat different character to those which precede 

 them ; the muscular sac of the gland is well developed and opens 

 on to the exterior at the same point as in the anterior segments ; 

 it differs in being furnished with a diverticulum which is nearly as 

 long as itself; the glandular region of the nephridium is more 



Proc. Zool. Soc— 1887, No. XL 11 



