12 ALFRED GIBBS BOURNE. 
genus which I have come across. I speak of it for the present 
as Perichzta. 
MAHBENUS, gen. nov. 
Set very numerous. Circles of sete almost continuous. 
Clitellum extends over more than three segments. 
Male pores, one pair, very close together, no sete between 
the male pores. 
Gizzard occupies not more than one segment. 
Intestinal ceca absent. 
Septa normal. 
Micronephridia present. 
Testes, two pairs, freely exposed. 
M. imperatrix, sp. nov. 
Length 650 mm. Circumference 35 mm. 
Segments 200. 
Colour rich dark brown, lighter on the ventral surface. 
Prostomium encroaches very slightly upon the peri- 
stomium. 
Seta.—Segment 11, 52; Segment v, 80; Segment 1x, 110; 
no modified setze ; setee remain in the clitellum. The circles 
of sete are continuous in Segments 11—xvii and xIx, the circle 
is interrupted ventrally in xv111 by about eight seta gaps, and 
in all the posterior segments there is a tiny gap recognisable 
only with care in the median dorsal and ventral lines. 
Clitellum not strictly confined to particular segments, may 
extend over Segments xiv—xr1x and part of xx. 
Genital Apertures.—Male pores very small and quite close 
together (with not much more than a seta gap between them) ; 
the region immediately around them becomes raised into an 
oval papilla after killing in spirit. Two pairs of glands open 
in the region of the male pores, one pair on Segment Xvii 
behind the circle of set, and one pair between Segments x1x 
and xx; their apertures lie about as lateral as seta 6. 
The oviducal apertures are paired. 
The spermathecal apertures are very small, and placed 
