82 Mr. F. E. Beddard on a 



glandular jyart is lined hy a single row of glandular cells , 

 which are less stained than the surrounding tissues and 

 are filled with excreted granules. In the Acantliodrilidee, 

 and, in fact, in all other earthworms with tubular atria, the 

 epithelial lining is divisible into two distinct layers, with cells 

 of a different character in each. The Moniligastridte are 

 partially at least an exception to this rule ; and so too is 

 Ocnerodrilus, one of those forms which stand on the border- 

 line between the " Terricolge " and the " Liniicolaj " of 

 Clapar^de. The structure of the atria of the last-mentioned 

 genus appears in fact to be exactly similar to that of Gordio- 

 drilus. The reduction of the two layers of epithelium to one 

 may perhaps be regarded as a degeneration, correlated possi- 

 bly with the small size of the worms \ but against this 

 hypothesis is the fact that species quite as small as these 

 have atria with the normal two layers of cells. 



The ovaries occupy the usual position in segment xiii. ; 

 like the testes they are pressed close against the parietes of 

 the body by the septum separating segments xii./xiii. The 

 oviducts open into the xiiith segment opposite to the ovaries, 

 and on to the exterior upon the xivth segment. There is no 

 receptaculum ovorum. The spermatothecce are two pairs, which 

 are large and oval in form j each narrows abruptly to form a 

 very slender duct of considerable length ; there are no di- 

 verticula. 



2. Gordiodrilus rol)ustus, sp. n. (PI. VII. figs. 4, 5, 6 B.) 



I have investigated three specimens of this species ; it is a 

 native of Lagos, West Africa. Two individuals were studied 

 by means of longitudinal sections ; the third was dissected. 



External Characters. 



The species is a small one, measuring only 32 millim. 

 after preservation with Perenyi's fluid, followed by alcohol. 

 The sizes of three of the species of Gordiodrilus described in 

 the present paper are shown in fig. 6. 



The individual of Gordiodrilus rohustus selected for 

 measurement consisted of ninety segments. The clitellum 

 extends from the middle of the xiiith to the end of the xviith 

 segment ; a narrow median area corresponding to the inter- 

 space between the ventral setas is entirely unmodified. The 

 clitellum is very thick, and stands out from the rest of the 

 body in the living as well as in the preserved worm. 



The setse are strictly paired, and lie upon the ventral 

 surface; the two lateral pairs are separated from each other 



