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Show 1879.] REV. O. P. CAMBRIDGE ON N E W ARANEIDEA. 291 GASTERACANTHA OBSERVATRIX, sp. n. (Plate XXVII. fig. 21.) Length of the transverse diameter of an adult female, exclusive of the spines, 4^ lines ; length of longitudinal diameter rather more than 2\ lines. This Spider belongs to the G. mammosa, C. L. Koch, group ; the spines are small, the intermediate and posterior ones being of the same length, and issuing from large circular prominences of the abdomen, which may, however, be really taken to form part of the spine itself. The cephalothorax rises to a single undivided, blunt, conical eminence on the middle of the caput; its colour is reddish yellow-brown, darkest on the sides and thorax, and clothed thinly with grey hairs, of which some form a marginal hand. The legs are dull yellow, marked and irregularly annulated with reddish brown. The abdomen is yellow-brown, clothed with grey hairs, and marked and marbled on the upperside with clearer yellow patches of different sizes, forming roughly an anterior curved band and a central large cruciform marking. The sigilla are normal in number (10 in front and 9 behind); but the four centrals of the front row are as large, or nearly so, as any of the rest; in fact the two fore centrals are the largest of all. Along the central longitudinal line are some small supernumerary sigilla. Examples of this Spider, which is allied to Gr. roseolimbata, Dol., and G. canningensis, Stol, were received from the Pratos Reef in the China seas, where they were taken by Dr. C. Collingwood, M.D., and kindly sent to me, some years ago. GASTERACANTHA PROBA, sp. n. (Plate XXVII. fig. 22.) This Spider is of a quadrate form, a little narrower behind, and with the posterior outline somewdiat curved, and is allied to, but, I think, distinct from, G. cicatricosa, C. L. Koch. In the adult female the length of the longest transverse diameter (which is at the fore margin) is 3| to 4 lines ; longitudinal diameter 2f to 3 lines. The abdominal eminences on which the spines are placed are small. The spines are very small, sharp-conical, and scarcely differ in size ; the anterior ones are placed, one at each extremity of the fore margin (which is but very slightly curved); they are slightly the smallest, and are directed a little forwards ; the intermediate spines are a little directed backwards, and about equally divide the space between the anterior and posterior ones ; but as the hinder division of the abdomen, on which the latter are placed, is more liable to shrink in preservation than the rest, the interval between the intermediate and posterior spines is sometimes less than that between the former and the anterior ones. The cephalothorax is less raised at the caput than in most other species of the genus ; the caput also, instead of being elevated in the middle, has a longitudinal furrow along that part; its colour varies from brownish yellow to dark blackish brown; and it is clothed with short erev hairs. • * 19* |