Dr. L. Moysey — Coal- measure Arthropods. 



505 



which covers and obscures the radiating coxae of the appendages 

 which are just indicated beneath it. On the right side of the head 

 are seen the fragments of a stout femur and patella of one of the 

 ambulatory legs, probably the first, and on the left side, running parallel 

 to the body, is another appendage, probably the fourth walking-leg. 

 This leg extends backwards as far as the eighth segment of the body. 

 The opisthosoma is perfect and gives the dorsal aspect of the animal. 

 It consists of the normal eight segments. There is no evidence of the 

 single pair of laterally placed tubercles on each terga, mentioned by 

 Mr. Pocock, but these are probably obscured by the quantity of white 

 deposit which is especially marked in that region. 



FlG. 11. Opisthosoma of zin Antliraco- 

 martus. Dorsal view. Newthorpe, 

 near Eastwood, Notts. Three times 

 nat. size. 



Fig. 12. Counterpart of Fig. 

 showing anterior somite. 



11, 



Figs. 11, 12, Anthracomartus, indet. A beautiful little fossil obtained 

 from the Newthorpe Clay-pit. Nottinghamshire, opened in the measures 

 between the AVaterloo and Ell Coals, presents the opisthosoma of an 

 Arachnid. It shows the posterior six segments. The first segment 

 visible on the fossil is very narrow, about one-quarter the length of the 

 succeeding segments ; its anterior border is prolonged medially into 

 a sharp projection, hence the anterior border appears as if defined by 

 a well-marked bracket-shaped line. This segment apparently has no 

 lateral lamina?. The counterpart of this specimen is very imperfect 

 (Fig. 12), but gives yet another anterior segment which is not traceable 

 on the fossil. It consists of a very short V-shaped segment placed in 

 an inverted position anterior to the bracket-shaped border of the other 

 segment, and separated from it by about its own width of matrix. 



The other segments are equal in length, each posterior border being 

 parallel to the next. Owing to the fossil being uncompressed, each 

 lateral lamina is bent over in a bold curve, thus giving to the specimen 

 a transversely arched appearance, and they are at the same time directed 

 slightly backwards. These laminae are ornamented with irregularly 

 placed, Avell-marked tubercles, larger towards the lateral margin. On 

 the left side the lateral laminae (and the ultimate segment) appear to 

 have been removed, leaving the impression of their underside, so that 

 the tubercles look like pits, and also demonstrating a divisional line 

 between the terga and their respective laminae. The rest of the 

 segment is smooth. The ultimate segment consists of a more or less 

 quadrate area, with its two lateral laminae directed outwards and 

 backwards, their posterior border being in contact with the posteriorly 



