AN ATTEMPT TO CLASSIFY EAETHWOEMS. 255 



Spermathecse very minute and numerous, being from two to 

 four pairs in all or some of the Somites xii to xv. 



Nephridia very large, and of a peculiar form, each consisting 

 of a greatly coiled tubule, arranged as a tuft, communicating 

 with a large duct, which is produced into a great sac-like out- 

 growth. This caecum is less developed in the anterior somites ; 

 and is most feebly marked in the first pair of nephridia. 



Gizzard in Somite vi. 



A single pair of oesophageal glands in Somite ix, or partly 

 in VIII and partly in ix. 



The dorsal vessel is doubled anteriorly and specially enlarged 

 in Somite viii. 



Lateral hearts, vi — xi.] 



Species 1. M. rappi, F. E. B., 1885; Cape of Good 

 Hope. 

 2. M. beddardi, W. B. B., 1886; Natal. 

 See Beddard, ' Trans. Zool. Soc.,* xii, 1886 ; Benham, ' Quart. 

 Journ. Micr. Sci.,^ xxvi and xxvii. 



Genus 26. Urobenus, W. B. B., 1886. 



Setae in couples. 



Clitellum occupies Somites xiv to xxv, incomplete ven- 

 trally. 



Spermiducal pore on Somite xx. 



Nephridiopores in a line with the outer setae. 



Sperm -sacs two pairs, of which one pair is in Somites xii 

 and xiii, the second pair in Somite xiv. 



Peculiar '^ pyriform sacs " occur in pairs on the ventral 

 surface of the body-wall opening externally ventrad of the 

 inner setae, commencing in Somite x. 



Testes and ciliated rosettes in Somites xii and xiii. 



[Spermathecae three pairs, in Somites vii, viii, and ix. 



Gizzard in Somite viii. 



Three pairs of flask-shaped calciferous glands in Somites 



IX, X, XI. 



M. rappi I fiud no trace of setse in the peristomium— the fusion is com- 

 plete. 



