506 R. I. Pocock—Carboniferous Arachnida. 
Again, in the dorsal view of P. bohemica (text-fig. 20, p. 19), the 
outer moieties of the posterior four pairs of pleural lamine are 
marked with an additional concentric sulcus, which is continued 
across the unpaired lamina of the last tergal plate. This is no doubt 
the sulcus defining on the ventral side the outer plate of the lamin, 
which is present in all the well-preserved specimens of Anthracomartus 
that I have seen. 
One other difference, already referred to, between Promygale 
bohemica and the species of Anthracomartus is the presence in the 
former, to judge from the drawings, of an additional tergal plate, 
cut off by a sulcus from the posterior half of the seventh tergum, 
making eight of these plates visible on the dorsal side. Apart from 
the fact that this plate is not so divided, either in Hophrynus, 
Anthracosiro, or Anthracomartus, a fact sufficient in itself to cast 
doubts upon the reality of its segmentation in Promygale bohemica, it 
is noticeable that Fritsch himself omits the sulcus in question from 
his drawing of P. elegans (fig. 26, p. 21), and thus does not ascribe 
even a generic value to its presence in P. bohemica. Without further 
evidence I find it hard to believe in its existence. 
With regard to the restoration of the ventral side of the same 
species (text-fig. 21), since the posterior margins of the sterna are 
represented by dotted lines, it may be assumed that these plates were 
cracked and obliterated beyond the possibility of accurate decipherment. 
All the more remarkable, therefore, must be regarded the circumstance 
that the so-called comb-like organs are so well preserved as to admit of 
detailed restoration. I suggest that these alleged organs are really 
the two deep impressions which lie, one on each side, of the anterior 
sternal plates in Anthracomartus. The settlement of this question, 
however, must be left until an opportunity of examining the fossil has 
been afforded to some competent Arachnologist. 
Respecting the shape of the sternal plates as indicated on this 
drawing, it is noticeable that Fritsch has represented them by dotted 
lines running parallel with each other and at right angles to the 
longitudinal axis of the body, whereas the drawing of the original 
specimen of P. elegans (pl. xv, fig. 4) shows quite clearly that the 
sterna, at least in the posterior part of the body, are angularly 
curved in the middle line, exactly as in the examples of Anthracomartus 
that I have seen, thus establishing another point of similarity between 
this genus and Promygale. 
In referring the genus Promygale to the Aranez and Anthracomartus 
to the Opiliones, in spite of the striking similarity between them, 
Fritsch relies upon his alleged discovery of jointed appendages, 
representing the spinning mamille of the Aranez, upon the lower side 
of the opisthosoma in Promygale and their absence in Anthracomartus. 
In the restoration of P. elegans (text-fig. 26, B, p. 31) these 
appendages are shown as two pairs of slender three- or four-jointed 
limbs attached to the second and third sternal plates, each limb of 
a pair being widely separated from its fellow of the opposite side. 
I cannot think the drawings of the original specimens justify this 
conclusion. In fig. 3, pl. xv, showing the ventral side of P. elegans, the 
author has portrayed pieces of what he regards as small limbs scattered 
