70 TERRESTRIAL CARBONIFEROUS ARACHNIDA. 



very distinct terga, and in front of the seventh from the end (the first large tergal 

 plate) one, or possibly two, narrower terga. The pleural plates quite small on the 

 anterior terga, but becoming progressively longer from before backwards and tilted 

 upwards and inclined backwards, so that the anterolateral angle of each is obtuse 

 and the postero-lateral angle acute ; each composed of a single plate as in 

 Eoplirynus and Kreischeria, not of a double plate as in Anthraccmartus. Appen- 

 dages as in the other members of this order. 



Type Species. — Antlivacosiro woodwanli, Pocock. 



Anthracosiro woodwardi, Pocock. Text-figures 35, 36. 



1903. Anthracosiro woodwardi, K. I. Pocock, Geol. Mag. [4], vol. x, pp. 246—250, 405—408. 

 1909. Anthracosiro latipes, E. L. Gill, Trans. Nat. Hist. Soc. Northumb.. Durham, Newcastle-oii-Tyne, 

 vol. iii, pp. 510 — 522, pi. xiii. 



The type of this species is a specimen (No. I. 1551) in the British Museum, 

 showing clearly the structure of the terga of the opisthosoma, portions of the 

 walking legs and the carapace in vague outline. A second specimen (No. 1. 1554) 

 shows little more than the last, except that the radial arrangement of the coxa? of 

 the limbs can be indistinctly deciphered. A third specimen (No. I. 1553), however, 

 which I had not seen in 1903, has the carapace well preserved. Since this plate 

 was previously unknown it is worth describing in detail. 



It is wider than long, elevated and longitudinally convex mesially, but sloping 

 away anteriorly, posteriorly and laterally from the highest point, which is situated 

 near the centre of the dorsal surface. Anteriorly a distinct T-shaped ridge is 

 traceable; the ridge representing the stem or upright portion of the letter lies in 

 the middle line, and extends from the anterior edge of the carapace upwards to 

 meet the ridge representing the transverse bar of the T. At each extremity of 

 this an eye was probably situated. On each side of the median ridge there is a shallow 

 depression. Behind the transverse ridge there extends backwards to the posterior 

 border of the carapace a pronounced depression bordered on each side by a ridge, 

 and constricted near the middle of the carapace so as to present the appearance of 

 two triangular depressions set angle to angle, the posterior being much the larger 

 of the two. Outside the ridge on each side there is a rather wide and deep 

 longitudinal depression. Another depression, running transversely and continuous 

 with the posterior angles of the median depression, is traceable in front of the 

 posterior border of the carapace. Portions of the terga of the opisthosoma and of 

 the appendages add nothing to our knowledge of these structures, with the 

 important exception that a detached palpus shows this appendage to have been 

 short and stout, the femur being especially strong and deep, with a rounded 

 prominence near its base on the inferior edge. 



Approximate measurements in mm.— Length of carapace 5"7, width (3; length of 



