30 



TERRESTRIAL CARBONIFEROUS ARACHNIDA. 



length is about 15 - 5 mm., the opistliosoma being 9 - 5 mm. and the pi'osoma 6 mm., 

 the width of both regions being about 3 mm. There is a distinct spiniform 

 process at the anterior extremity of the carapace as in certain recent forms, e. g. 

 LabocMrus. 



In Dr. Moysey's Collection there is a specimen from the Shipley Claypit with 

 the dorsal side exposed (PI. II, fig. 8). The anterior portion of the carapace is 

 broken away, showing vaguely the coalesced coxa? of the chela? and the distal 

 portion of the right chela. Behind the posterior border of the carapace there is a 

 triangular plate which I regard as the posterior sternal plate of the prosoma, the 

 exposure of which suggests that the overlying dorsal area was membranous ; on 

 each side of it may be seen the coxa? of the legs of the last pair. Nine terga of 

 the opistliosoma are clearly discernible, but the three terminal segments of this 



Fig. 9. — Geralinura britannica, sp. n. ; restoration of ventral surface, three times nat. size. — Coal 

 Measures ; Coseley, near Dudley. W. Madeley Collection. 



region are vaguely defined ; they appear, however, to be comparatively large both 

 in length and width ; the post-anal flagellum is not preserved. Both the carapace 

 and the terga and lateral membrane of the opistliosoma are granularly coriaceous. 



Measurements in mm. — Total length about 20 ; length of opistliosoma 13, its 

 length, excluding the last three segments, 10, its width 6; length of chela, 

 excluding coxa, 7. 



This specimen is a little larger than the type and has the chela? decidedly longer. 

 The difference in length, however, both of the body and the chela, may be attribut- 

 able to age ; and since the males of recent species very commonly have the chela? 

 much longer than they are in the females, it would be rash to attach specific 

 importance to the difference observed, even if the type specimen were known to 

 be fully adult. 



