514 AN ARACHNID FROM THE COAL 



constricted behind. The relief of the cephalothorax is mainly 

 related to structures on the ventral surface ; there is nothing 

 suggestive of a carapace such as that of Pocock's Anthracosiro 

 fntschu, which he takes to be characteristic of the genus, 

 except that to the right of the middle line near the front there 

 is a tubericle much resembling the eye of that species. Its 

 position is seen in fig. 7. On the left side raised impressions 

 of four coxae are conspicuous, their outer edges enclosed by a 

 line of integument forming the margin of the cephalothorax on 

 that side. The last coxa appears to have been longer than 

 the others, as it frequently is in allied forms, and to have 

 overlapped the anterior border of the abdomen. The right 

 side of the cephalothorax is in a rougher state and its detail 

 cannot be interpreted with certainty ; but some irregular ridges 

 with a generally radial disposition no doubt mark the positions 

 of the coxae on that side also. Seen in the light in which the 

 drawing reproduced in fig. 2 was made there is little sign of 

 symmetry in the cephalothorax ; but with the light falling on 

 it from behind, the structural details shown in fig. 7 appear. 

 There is a central, somewhat rounded mass, from which ridges 

 radiate between the coxae. The whole presumably represents 

 part of the chitinous strengthening' of the sternal area ; of an 

 actual sternum there is no recognizable trace. The shape 

 given to the sternal area enclosed by the coxae in the restored 

 outline (fig. 4) is that suggested by the fossil, but it is 

 ' naturally very largely guesswork. The hindermost portion 

 of the cephalothorax is formed by a straight, flattened, trans- 

 verse strip, an arrangement which is very common among the 

 Anthracomarti. 



The abdomen is united to the cephalothorax by the whole 

 width of its anterior end. In general shape (see fig. 4) it is 

 an oval, with the broader end to the rear. On a first inspection 

 the fossil itself gives an impression of a nearly parallel-sided 

 abdomen, but a closer examination shows that this is mis- 

 leading. At the posterior end the border, though seemingly 

 clean-cut, is not complete all round, as is seen on comparing 

 the parts of the segments to right and left of the anal valve. 



