Genera and Species of Trapdoor Spiders. 191 
Legs and palpi as in Paramigas, but the legs not woolly 
beneath ; the impression of the upper surface of the tibia 
of the third deeper, atid a cluster of spinules at the distal end 
of the upper surface of the first and second tibiz; a couple 
of slender spines on the lower surface of the protarsus of the 
fourth ; claws of first and second legs armed with a couple of 
long teeth, those of the third leg with one long tooth and a 
small one behind it, that on the fourth with one long tooth. 
Abdomen and spinners as in Paramigas. 
Micromesomma Cowani, sp. n. 
Colour deep yellowish brown throughout, a little paler 
below ; abdomen blackish grey. 
Measurements in millimetres.—Total length of trunk 16:5, 
of carapace 5:5, width of latter 5; length of first leg 11, of 
second 10, of third 9°5, of fourth 13. 
Loc. Central Madagascar (Rev. Deans Cowan). 
THYROP@US, gen. nov. 
Carapace very slightly longer than wide, smooth, with 
cephalic region high, wide, and convex, with the sides nearly 
perpendicularly sloped, widest between the coxee of the second 
pair of legs, very strongly narrowed backward from this 
point. Fovea as in Paramigas, but not angular, only lightly 
recurved, the median impression projecting further back- 
wards than the lateral; the cephalic sulcus and impressions 
shallow. Ocular area very wide, half the length of the cara- 
pace and about twice the width of the fovea; eyes of anterior 
row straight, of posterior row slightly recurved and not so 
wide ; all the eyes small, the lateral particularly being in- 
distinct ; the median eyes on a very low tubercle, separated 
by a space which is slightly larger than their diameter, but 
which is barely one third of the space between them and the 
lateral, which are smaller and very narrow, almost linear ; 
the posterior lateral also nearly linear, separated from the 
anterior lateral and from the posterior median by spaces which 
are a little greater than the distance between the anterior 
medians; the posterior median eyes a little smaller than the 
anterior median. Clypeus very large, its length equal to the 
distance between an anterior median and anterior lateral eye. 
Mandibles constructed as in Paramigas, but relatively 
stronger; the inferior edge armed externally with 3 or 4 
strong teeth and internally with 4; the space between them 
finely denticulate; some of the sete on the inner surface 
