202 Mr. J. Black wall on new Species of Spiders. 



of their fossils in collections, having given Sir Roderick Murchison 

 the erroneous impression that his. Upper and Lower Silurian 

 groups of fossils (the distinctness of which he himself was the 

 first to point out) were mixed together in the Caradoc Sand- 

 stone, and that consequently the Bala beds, identical in fossils 

 with those of the Caradoc beds (although formerly recognized 

 by him as the type of the Cambrian system), could not be sepa- 

 rated palseoutologically from the Upper Silurian group. The 

 Mayhill Sandstone was one of the first formations I recognized, 

 on landing near Melbourne, with the usual Upper-Silurian 

 fossils ; and it is now found here, as in Wales, to be slightly 

 unconformable to the Cambrian or Lower Silurian, forming the 

 obvious base of the former and totally distinct from the latter. 



XXIIL — Notes on Spiders, ivith Descriptions of several Species 

 supposed to be new to Arachnologists. By John Blackwall, 



r.L.s. 



Tribe Octonoculina. 



Family Mygalid.e. 



Genus Filistata, Walck. 



Filistuta distincta, n. sp. 



Length of the male (not including the falces) -j^ of an inch; 

 length of the cephalothorax -^, breadth -^\- ; breadth of the ab- 

 domen -^; length of an anterior leg 1-]-; length of a leg of the 

 third pair -}-§■ ; length of a palpus ^. 



The cephalothorax is oval, clothed with yellowish-grey hairs, 

 moderately convex, with a longitudinal indentation in the medial 

 line, and an abrupt prominence in the cephalic region, on which 

 the eyes are seated, the space between the prominence and the 

 frontal margin being sloped forwards; its colour is brownish 

 yellow, the medial region being the darkest. The falces are 

 small, subconical, prominent, united at the base, somewhat 

 hollowed on the inner surface, armed with a very short, curved, 

 red-brown fang, and have a pointed tooth near their extremity, 

 on the inner side ; the maxillpe, which are strongly curved to- 

 wards the lip, have the palpi articulated on the outer side, 

 nearer to their extremity than their base ; the lip is long, and 

 somewhat pointed at its apex ; and the sternum is oval and 

 hairy. These parts have a brownish-yellow hue, the falces, 

 which are rather the darkest- coloured, being tinged with red at 

 the extremity. The eyes are closely grouped on the cephalic 

 prominence, and are diaphanous ; three on each side, of an oval 

 figure, form an irregular triangle, the anterior ones being the 



