1899.] AWD SPIDERS FEOM TROPICAL WEST AFRICA. 865 



described it in 1858. Hence its generic position has remained a 

 matter of doubt. 



Thalassius formosus, sp. n. (Plate LYII. fig. 19.) 



2 ■ Resembling the preceding in its robupt, thickly plumose legs, 

 form of vulva, &c. ; but differing essentially in colour. Side of 

 carapace covered with a thick coating of yellow hairs, with a 

 narrow brown inferior baud above the black border ; npperside 

 mostly covered with deep-brown hairs, which on each side invade 

 and break the continuity of the lateral yellow posterior area. 

 Clypeus brown, the brown area sharply defined at the sides by the 

 yellow hair clothing the sides of the head. Upperside of abdomen 

 yellow and rich olive-brown, the latter arranged in distinct 

 patterns, forming a posterior median patch, in front of which there 

 are five transverse stripes, the anterior broader than the posterior ; 

 also small deep brown spots scattered here and there on the yellow, 

 and the blood-red patches noticeable on guineensis also present. 

 Upperside of legs yellow, banded with brown ; femora with a 

 broad basal brown band and a narrower band of the same colour, 

 about one fourth of the distance from the apex ; patella brown, 

 slightly yellow distally ; base of tibia narrowly, apex more M'idely 

 brown ; base and apex of pro tarsus and of tarsus brown. 



Measurements in millimetres. — Total length 21 ; length of cara- 

 pace 10, 1st leg 35-5, 2nd leg 36, 3rd leg 33, 4th leg 38. 



Loc. Benito Eiver (6r. L. Bates). 



Although not quite adult, the type of the species shows the same 

 form of vulva as in subadult examples of T. c/uineensis. 



Thalassius inorsatus, sp. n. 



2 . Colour much as in T. guineensis ; carapace and abdomen 

 covered with a uniform mixture of brown and yellowish-grey hairs; 

 abdomen ornamented posterioi-ly at the sides with some blood-red 

 patches running into ill-defined stripes ; integument of abdomen 

 olive-yellow, with a median anterior pale narrow lanceolate area ; 

 legs uniformly brown, covered with greyish-white hairs. 



Carajjace a little less than tibia of 1st and 4th and than pro- 

 tarsus of 4th leg, slightly longer than protarsus of 1st. 



Legs much less thickly plumose than in guineensis ; patella and 

 tibia of 4th a little less than those of 1st. 



Lower side of ahdomen covered with short slender hairs, inter- 

 spersed amongst the normal hairy coating. 



Lateral lobes of vulva irregularly subquadrate ; the inner edge 

 longitudinally truncate and almost contiguous throughout their 

 length, being merely separated for a short distance anteriorly by a 

 narrow median sclerite ; anterior depression of vulva marked with 

 a pale membranous spot on each side, and on the inner side of the 

 spot with a black, thickly chitinous ridge. 



Loc. Benito Eiver {G. L. Bates). 



In colour, &c., closely resembling the Somaliland species T. 

 unicolor Simon (in Donaldson Smith's ' Through Unknown African 



