MEASURES OF THE TYNE VALLEY 52 1 



also on the right, the angle of tilt gets steeper with each leg 

 from the first to the last. The femur of the first leg is not far 

 from the horizontal, that of the last appears to be vertical, and 

 the intermediate femora lie at intermediate angles. This pro- 

 gressive tilting of the femora must be borne in mind in looking 

 at fig. 8, an attempt to restore the proximal joints of the legs 

 from what is seen of them in the fossil. The shape of the 

 trochanters is more or less based upon the rather well defined 

 structure lying in front of the cephalothorax on the right, 

 which is very probably the trochanter of the first leg on that 

 side. 



As to the general systematic position of the arachnid repre- 

 sented by this fossil no prolonged discussion is necessary. 

 Whatever the Anthracomarti (Meridogastra) may be, there is 

 no question but that this is one of them. To place it in any 

 of the established genera of the group is more difficult. A 

 number of characters, however, indicate that it is very near to 

 Anihracosiro, if not actually a member of the genus. Indeed, 

 allowing for the differences to be expected between a dorsal 

 and a ventral exposure, it even agrees very fairly with 

 A. ivoodwardi Pocock*, the type species of the genus (fig. 5). 

 The length of the body is practically the same. The general 

 shape is a little different, the Crawcrook specimen being 

 rather broader behind : but this may readily be due to different 

 conditions of fossilization. The segmentation of the abdomen 

 agrees very closely in the two forms ; in number, size, and 

 shape the plates are nearly identical, the only conspicuous 

 difference being that in the present specimen there is no suture 

 between the median plates and their lateral laminae; and this 

 is a difference that is normal in the ventral plates of Anthraco- 

 marti as compared with the dorsal. The anal plates, the 

 unusual position of which is a striking feature in the Craw- 

 crook fossil, cannot be compared directly with the same parts 

 in Anihracosiro. But in Pocock's specimens of A. woodwardi 

 the impression of the underlying circular anal plate, though 



* R. I. Pocock. A New Carboniferous Araclinid. GeoL Mag-., 1903, p. 247. 



