Mr. J. Blackvvall on newly discovered species. 0/ Araneidea. 173 



five ocular plates are small and heart- shaped, their apex is di- 

 rected towards the anal opening, and their base to the area ; the 

 madreporiform tubercle is slightly elevated on the single ovarial 

 plate, and the surface of the discal plates is almost destitute of 

 sculpture or granulation. 



Affinities and differences. — D. Mooreii resembles D. depressum, 

 Ag., in the depression of its upper surface and the flatness of its 

 base, likewise in having the tubercles of both areas of nearly a 

 uniform size around the base ; but it is readily distinguished 

 from D. depressum by the number and greater development of the 

 tubercles of the ambulacra, which maintain their size throughout ; 

 whilst in D. Mooreii the ambulacral tubercles are fewer in num- 

 ber and rudimentary in size in all the upper part of the areas. 

 The contour of the test moreover does not assume the penta- 

 gonal outline of D. depressum, nor has the upper surface of the 

 interambulacral areas the median depression seen on the test of 

 the latter. The mouth-opening is larger, and the decagonal 

 lobes are more equal in size in D. Mooreii than in D. depressum. 



Locality/ and stratigraphical range. — We have collected D. 

 Mooreii in the Upper Lias of Gloucestershire. Mr. Moore found 

 it in the same stratum near Ilminster with Ammonites communis 

 and A. serpentinv^. Professor Deslongchamps has communicated 

 a specimen of this Urchin which he found in the Lias superieure 

 of May, Calvados, associated with Leptcena Davidsonii and The- 

 cidea Bouchardii and several other species. 



We dedicate this species to Mr. Moore, of Ilminster, whose 

 assiduous researches have brought to light so many interesting 

 forms from the Upper Liassic beds of Somersetshire. 



[To be continued.] 



XVn. — Desa'iptions of some newly discovered species 0/ . 

 Araneidea. By John Blackwall, F.L.S.j, r "f " 



Tribe OCTONOCULINA. 



Family Salticid^. 



Genus Salticus, Lair. 



>fii ot qn tmb 



Salticus promptus. 



Length of an immature female 2%ths of an inch; length of 

 the cephalo-thorax -j'^; breadth -^^) breadth of the abdomen 

 j\j ; length of a posterior leg y^^j ; length of a leg of the second 

 pair tV- 



The cephalo-thorax is large, glossy, nearly quadrilateral, ab- 



