310 W. BLAXLAXD BEXHAM. 



has also figured similar diflFerent regions in All ur us (4, pi. xxv, 

 figs. 11, 12). 



Spencer (30) describes and figures (pi. vi, fig. 26) for Megas- 

 colides the funnel and ciliated prseseptal region of the large 

 posterior nephridia, as well as the "wide^^ intra-cellular tube 

 which passes into the body-wall as far as the circular muscles. 

 At the junction of this layer with the epidermis a group of 

 muscle-cells, arranged as a sphincter around the nephridial 

 tube, is shown, and has a great resemblance to the condition 

 found in Criodrilus (PL XXIV, fig. 17). Spencer also gives 

 some details as to the opening of the small nephridia to the ex- 

 terior, in which there is a short intercellular portion interposed 

 between the epidermic pore and the intra-cellular tube. 



Perrier some years ago (26, pi. xvi, figs. 38, 39) described 

 with some detail the nephridium of Urochaeta. He seems to 

 imply that the whole tube is ciliated, with the exception of a 

 very small muscular duct. More recently Beddard (3 and 6) 

 has paid more attention to this genus. He indicates at least 

 two regions (the " narrow" and ^^ middle" tubes) ; he does not, 

 however, represent the cilia, which I believe are present only 

 in certain tracts, and not throughout. 



Pontodrilus was also investigated by Perrier (27), who 

 describes and figures (pi. xiv, figs. 10, 11, 13) the nephridia. 

 The anterior nephridia (in somites 14, 15, 16, 17) diS'er 

 slightly from the remainder, which have very abundant vesi- 

 cular cells around the convolutions of the tube, much as in 

 Enchytrseids. The tube appears from his description to be 

 similar throughout, for he speaks of it as a *' sinuous glandular 

 tube, ciliated internally throughout" its length. His figure 

 of a section closely resembles that of the ''middle" tube in 

 Lumbricus. 



In my first ' Studies on Earthworms ' (8) I figured and 

 described certain difierences in the character of the tube in 

 the nephridium of Microchseta rappi; and this genus I 

 have re-examined, and can confirm ray statements. 



I believe the above are the only earthworms in which any 

 attempt at histological detail has been made, and no author has 



