40 TERRESTETAL rARBONIFEROUR ARACHNIDA. 



its aiiterioi' ;nul iiostcrior Itordcrs are straii>]it and parallel, and llie })late does not 

 expand towards its antevioi' border, as in existing- genera, so that it may be 

 described as transversely oblong. The carapace is a little Avider than long, with 

 the lateral l)()i'ders convex, the widest point lying a little in front of the middle ; 

 its surface is moderately vaulted, its anterior portion being distinctly but evenly 

 curved downwards towards the edge to which the cucullus is hinged. A distinct 

 but shallow constriction marks the junction of the carapace and abdomen. The 

 latter is elongate and oval, rather wider than the carapace ; behind the Avidest 

 point in front, the sides are slightly convex and converge gradually towards the 

 posterior extremity, which show^s indication of a median lobate excrescence. 

 Portions only of some of the legs are preserved. Approximate measurements in 

 mm. : Total length 12'5; length of carapace 4"5, width about 5 ; length of cucullus 

 ], width 2"5 ; length of abdomen 8, width about 5. 



Thus these three specimens from Coseley, near Dudley, agree tolerably closely 

 in dimensions. The type of G. scahcr, Scudder, on the contrary, was larger, the total 

 length being 15 mm., the length and width of the carapace 5'25 mm., the length of 

 the abdomen 9'75 mm., and the width G'25 mm. These measurements may be 

 instructively compared with those oi Knstaracline «»Zt'«/a, Melander, from the same 

 locality, namely Mazon Creek, Illinois, the total length being 15 mm. and the 

 abdomen, without the " pygidium," mm., with a width of 7 mm. Thus there is the 

 same close agreement between the American specimens as between the English 

 examples. 



Gemis POLIOCHERA, Scudder. 



1838. ? CryjHostemma, Guc'rin-Mc'neville, Rev. Zool., p. 10. 



1884. Pollochera, S. H. Scudder, Proc. Amer. Acad. Arts Sci., vol xx, p. 16. 



1890. Poliochera, S. H. Scudder, Mem. Bost. Soc. Nat. Hist., vol iv, p. 444. 



Characters as above (p. 37). 



Poliochera alticeps, sp. nov. Tlate II, fig. G; Text-figure 14. 



Carapace elevated, convex from before backwards; the elevated area marked 

 with a median groove ending behind in an impression, and an impression, probably 

 muscular, far out on each side of this, a posterior curved groove passing on each 

 side into a deeper impression defining the elevated area behind ; the median 

 length of the carapace about equal to its posterior width and as long as the anterior 

 two large terga of the opisthosoina. 



Opisthosoma wider than the carapace, its width less than its length ; the 

 three large segments subequal in length ; each marked apparently with two 



