378 W. BLAXLAND BENHAM. 



The nephridia in Somite iv are slightly larger than those 

 immediately following, as Beddard has noted for M. Bar- 

 welli, the convoluted tube being thicker and whiter. I 

 have not been able to assure myself as to the external opening, 

 whether it is in the body-wall or in the stomodaeal wall, but I 

 believe the former. 



The nephridia are provided, as in other species, with a very 

 large muscular duct, forming a diverticulum. The coiled 

 tube is embedded in tissue, as in Lumbricus, and a fairly 

 extensive plexus of blood-vessels can be detected around the 

 tube, as in all other " earthworms '' except Ocnerodrilus, as 

 opposed to " waterworms." 



With regard to the vascular system I may merely state 

 that the dorsal vessel is single, and is not accompanied 

 by a supra-intestinal vessel. Four pairs of lateral hearts lie in 

 Somites vi, vii, viii, and ix; they are dilated and twisted, but 

 are not moniliform. The lateral hearts in M. Deshayesi are 

 in Somites vi, viii, and ix ; in M. Barwelli in vi — xiv. 



In M. Houtenii the dorsal vessel is doubled as in Acan- 

 thod rilus, and hearts in Somites vi — xi. A subneural vessel 

 exists, as Rosa has already stated ; this has not yet been 

 observed in any Microdrilid, but as it is frequently absent 

 in Microchseta, Photodrilus, and others amongst the 

 Macrodrili, no great stress can be laid upon its absence or 

 presence. 



The alimentary canal is constructed on the plan described 

 by previous authors. The gizzards, of which there are four, 

 lie in Somites xiii — xvi ; they increase in size from before 

 backwards, the fourth being nearly twice the width of the first 

 (fig. 3) ; they are very distinct, but are not so deeply marked 

 off from one another as Beddard figures (5, fig. 5) for M, 

 Barwelli. Behind each gizzard is an annular fibrous band, 

 apparently of connective tissue, for it appears white, and not 

 glistening, as do the gizzards. Perrier and Horst mention 

 them. Similar fibrous bands occur at the hinder end of 

 Somites xi and xii in front of the septum, and the wall of the 

 gut in Somite xii is distinctly more muscular than that of xi, 



