108 W. BLAXLAND BENHAM. 



Trigaster aud Beuhamia/'^ where I pointed out the various 

 differences between the two genera. Some of these differences 

 have been bridged over by various species of Beuhamia, 

 though in my opinion the genus Trigaster still stands as a 

 valid genus. 



Though I could find no pcnial chaetse on careful examination 

 of the partially dissected individual, I should not like to affirm 

 that they do not exist. There are several strong bands of 

 muscle in the Segments xvii to xxi (fig. 5), arising close to 

 the nerve-cord and passing outwards to be attached to the 

 body- wall near the dorsal midline; they have a similar ar- 

 rangement to those figured by me for Mouiligaster (indicus) 

 robust a, A. G. B.,^ and it is possible that special chsetse may lie 

 below these muscles — but I did not wish to do too much injury 

 to the specimen. 



The spermathecse, which lie in Segments vii and viii, 

 differ in size, as has already been noted in several species. 

 The anterior pair are smaller than the posterior pair, and 

 whereas the latter is provided with a small ovoid diverticulum, 

 those of the 7th segment are without one (fig. 6). Each 

 spermatheca consists of a thin-walled, somewhat ovoid sac, 

 with a longish and comparatively stout, muscular, glistening 

 duct, which widens as it approaches the body-wall. 



1 found no structures in these segments corresponding with 

 the pits noticed in the account of the external anatomy. 



The vascular system calls for a few remarks, but I have 

 not attempted to make a complete study of this system ; never- 

 theless, from what I have observed and from what previous 

 observers have noted, I believe the vascular system of Ben- 

 hamia and Acanthodrilus would repay a careful study on 

 the lines of and in relation to Dr. Bourne's thorough account 

 of the vascular system in Megascolex^ and Moniligaster.* 



» « Ann. Mag. Nat. Hist.,' 1890, p. 414. 



2 'Quart. Journ. Micr. Sci.,' vol. xxxiv, pi. 32, fig. 3. 



3 "On Megascolex coeruleus, &c.," 'Quart. Journ. Micr. Sci.,' vol. 

 xxxii, p. 49. 



'» "Moniligaster graudis," 'Quart. Journ. Micr. Sci.,' vol. xxxvi. 



