210 w. BLAXLAND BENHAM. 
size of an ordinary Tubifex—namely, about an inch in length. 
I found these worms amongst the roots of the bur-reed, which 
I was examining for Criodrilus, and with them I found 
a specimen of Spirosperma. Hitherto only two species of 
Stylodrilus have been described : the first by Claparéde,! St. 
heringianus; and the more recent species by Vejdovsky,’ St. 
gabretz. The differences—and these appear to me slight— 
between the two are such that had not Vejdovsky examined 
both species, one would be inclined to regard these differences 
as merely ones of observation. The specific characters of St. 
Vejdovskyi are as follows: 
Prostomium conical, two and a half times as long as the 
buccal segment, and differing in shape from both that of the 
previous species (Pl. VII, fig. 42). 
The segments, after the first three, are biannulated, the 
smaller annulus being anterior, asin St. heringianus. This 
annulus is very small in anterior segments, but behind 
the clitellum it is a third as large as the posterior annulus 
(Pl. VII, fig. 43). 
The chetz are essentially all alike ; in the other two species 
some of the ventral ones are simple sigmoid, unnotched chetz. 
In St. heringianus these are irregularly arranged, whilst in 
St. gabretz they occur only in the pre-genital bundles. But 
in the present species, though with a low power some chetz 
appear sigmoid, a high power reveals an indication of the 
notch; and the young, non-protruded chetz are notched as 
markedly as in the dorsal and posterior ventral cheetze (fig. 44). 
In fact, these anterior ventral chetz appear to have had the 
small upper tooth worn away. 
In St. Vejdovskyi, then, all the chete are notched; and, 
like those of Lumbriculus, have the distal or upper tooth 
much smaller than the lower. 
The dorsal vessel is not dilated in any segment; while in 
St. gabrete there are dilatations in Segments vi and vit. 
1 Claparede, ‘‘ Recherches sur les Oligochétes,’”’ ‘ Mém. Soc. Phys. et Hist. 
Nat. Genéve,’ xvi. 
? “System und Morph. d. Oligochaeten.’ 
