162 



BRITISH FOSSIL CRUSTACEA. 



(see ' Quart. Journ. Geol. Soc.,' xxv, p. 235). Mr. Brodie stated that the specimens collected 

 at that time and submitted to me were not considered to be new ; in fact, they consisted, 

 for the most part, of fragments of Pteryyotus 1 {P. Banksii) and Eurypterus 2 [E.pygmceus, 

 E. acuminatus, E. abbreviates, &c), already noticed in this Monograph and previously 

 described by Mr. Salter elsewhere. 



Since that communication was read, Mr. Brodie has again explored this locality, and 

 has forwarded to me several parts and an almost entire example of a Eurypterus, which 

 differs considerably from any species previously examined by me, and of which I subjoin 

 a short notice. 



The most perfect specimen, from which the restored outline (Fig. 53) is taken, 

 measures 2f inches in length and 10 lines in its widest thoracic segment. All the 

 somites are united; and one of the swimming-feet, although injured, is still in place. 

 The head, which is semicircular in outline, measures 4 lines in length by 9 lines in 



breadth ; the eyes are sub-central, and the ocelli nearly 

 central, as in the other species of Eurypterus. The first 

 six segments (thoracic) succeeding the head measure 

 together 9 lines in length ; commencing with a breadth 

 of 9 lines, they increase at the third segment to 1 lines, 

 and diminish at the sixth segment to 7 lines in breadth. 

 The segments increase in length and diminish in breadth 

 very evenly from the third segment backwards. The 

 borders of all the anterior segments are curved, and the 

 posterior angles slightly produced and acutely pointed. 



The six posterior (abdominal) segments diminish in 

 breadth backwards from 6 lines to 2 lines, and increase, 

 in the same direction, in length, from 1^ line to 2-| or 

 nearly 3 lines, the body being terminated by a slender 

 ensiform telson, or tail-spine, 7 lines in length. No 

 sculpture is apparent on the segments or head ; but the 

 integument composing the former indicates its tenuity by 

 abundance of plicae and wrinkles. The thoracic plate 

 (Fig. 53, 3) is very characteristic, differing in the form 

 of its median appendage from that of any previously 

 described species. It is 9 lines broad and 2^ in depth ; the median appendage is spindle- 

 shaped in outline, and is 'Z\ lines in length and \\ line broad. The swimming-foot is 2^ 

 lines in width and f of an inch in length, exclusive of the basal joint. The species agrees 

 closely, in the form of its swimming-feet, with the American and Russian Eurypteri, having 



Fig. 53. — Eurypterus Brodiei, H. Woodw. 



1. — Outline restored, natural size. Pas- 

 sage-beds from the Uppermost Silurian 

 to the Old Red Sandstone, Perton, near 

 Stoke Edith, Herefordshire. 



2. — Palpus (enlarged). 



3. — Thoracic plate (enlarged). 



1 See 'Mem. Geol. Surv.,' Mon. I, 1859, pi. xii, figs. 22—46, p. 51. 

 - 'Quart. Journ. Geol. Soc.,' 1859, vol. xv, pi. x, p. 229. 



