446 Dr. W. B. Benham on some 



segments. The pair of casca arise in segment xxvii., pass 

 through segments xxvi. and xxv., and are constricted at the 

 septa; each is a simple sac. 



The sperm-sacs are in segments xi., xii., and were hidden 

 by great quantities of gregarine and nematode cysts, which 

 are definitely external to the sperm-sacs. 



The spermatkecce are in segments viii. and ix. ; the sac is 

 globular, with a duct nearly half its length, and a diver- 

 ticulum narrow, nearly straight, but strongly curved at its end, 

 so as to resemble a golfing-club (fig. 6d). It is longer than the 

 sac and its duct. The sac and diverticulum were very con- 

 Bpicuous, owing to the white contents ; when teased, the sac 

 was found to contain, as usual, granular coagulated substance ; 

 the spermatozoa are confined to the diverticulum, and in the 

 enlarged terminal region are definitely arranged, all the heads 

 being densely packed against the wall, with the tails towards the 

 centre. It seemed to me that the heads of the spermatozoa are 

 different from those of Lumhricus in being pointed and curved 

 and shorter. In the duct of the diverticulum the spermatozoa 

 are quite loosely and irregularly arranged, and it appears as 

 if they were making their way upwards into the dilatation, 

 where they will be probably attracted by some chemotaxic 

 property of the epithelial cells, which secrete a fluid to bind 

 them together in a kind of spermatophore. 



The spermiducal gland is relatively small, and deeply lobed 

 in a somewhat fan-shaped fashion ; the duct is long, sharply 

 bent upon itself soon after leaving the gland, and then 

 running nearly directly to the body-wall (fig. Qc). 



The structure of the copulatory papillge could not be 

 properly studied owing to the imperfect preservation of the 

 worm ; but each consists essentially of clitellar cells, the 

 epidermis becoming suddenly thickened to about three times 

 the usual depth ; there is also a good deal of cellular tissue 

 developed amongst the circular muscles, reminding one of the 

 histological condition of the " capsulogenous glands " of the 

 common earthw^orm. 



This species may be diagnosed as follows : — 



Deep purple ; not banded ; measures 70-95 x 5 millim. ,• 116 

 segments. Male pores slit-like, not on a papilla; 

 separated by 5 chgeta. There is a cup-shaped papilla 

 laterad and mediad of each pore. A pair of similar 

 papillae on xvii. and xix. behind the chsetal ring. 

 Two pairs of spermathecae in viii. and ix., open ante- 

 riorly ; pores conspicuous ; each of these segments 

 carries a pair of cup-shaped papillae ; the whole in a 



