PLEURACASrTHID.E. 
7 
P. 1732. Distal two-thirds of small spine; locality unknown. This 
specimen shows several of the lateral denticles detached 
from the spine. Egerton Coll. 
42035. Portion of spine, probably of the same type as Nos. P. 1730 a 
and P. 3178 a'; Airdrie, Lanarkshire. Purchased , 1870. 
21423 a. Small spine, doubtfully assigned to young of this species ; 
Carluke, Lanarkshire. Purchased, 1847. 
P. 1181. Portions of two medium-sized spines, and the impressions 
of part of two others ; Middle Coal-Measures, Tingley, 
Yorkshire. Presented by the Earl of Enniskillen, 1882. 
P. 1183. Ease of a large specimen ; Tingley. 
Presented by the Earl of Enniskillen, 1882. 
P. 1179. Two abraded fragments, named P. erectus, J. AY. Davis ; 
Tingley. Presented by the Earl of Enniskillen , 1882. 
P. 531. Specimen referred to by Agassiz, loc. cit., under the name 
of P. planus ; Leeds, Yorkshire. Egerton Coll . 
P. 1178. Two specimens of the so-called P. pulchellus, J. IV. Davis; 
Tinglev. Presented by- the Earl of Enniskillen, 1882. 
P. 5170. Somewhat larger and much abraded, though similar spe¬ 
cimen; Longton, North Staffordshire. Purchased, 1885. 
P. 1733. Two small spines, one much abraded, probably young 
of this species ; Longton. Egerton Coll. 
Pleiaracantlms rebustns, Davis b 
1880. Pleuracantlms robustus, J. W. Davis, Quart. Journ. Geol. Soc. 
vol. xxxvi. p. 330, pi. xii. fig. 5. 
Type. Spine ; Davis Collection. - ’ 
Spine (so far as known) not attaining a greater length than 
0-13 m., almost straight, round or triangular in section, flattened 
posteriorly. Denticles large, robust, sharply pointed, arranged in 
series along each margin of the posterior flattened area. 
Form. &f Loc. Middle Coal-Measures : Yorkshire. 
P. 1177, P. 1180. Live incomplete specimens ; Tingley. 
Presented by the Earl of Enniskillen, 1882. 
21423. Lour small spines, doubtfully associated with this species; 
Coal-Measures, Carluke, Lanarkshire. Purchased, 1847. 
1 It is not improbable that the so-called Comgsacanfhus triangularis is 
founded upon an abraded spine of this species (J. W. Davis, Quart. Journ. 
Geol. Soc. vol. xxxvi. (1880) p. 62, vvcodc.). 
