PLEURACAUTHIDvE. 
7 
P.1732. Distal two-thirds of small spino ; 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 ; lliddle Coal-Measures, Tingley, 
Yorkshire. Presented by the Earl of Enniskillen, 1882. 
P. 1183. Base of a large specimen ; Tingley. 
Presented by the Earl of Enniskillen, 1882. 
P. 1179. Two abraded fragments, named P. erectus, J. W. Davis ; 
Tingle}'. Presented by the Earl of Enniskillen, 1882. 
P. 531. Specimen referred to by .\gassiz, lor, cit., under the name 
of P. planus ; Leeds, Yorkshire. Egerton Coll. 
P. 1178. Two specimens of the so-called P. pulchellus, J. W. Davis ; 
Tingley. Presented by the Earl of Enniskillen, 1882. 
P. 5170. Somewhat larger and much abraded, though similar spe- 
cimen; Longton, North Staffordshire. Purchased, 
P. 1733. Two small spines, one much abraded, probably young 
of this species ; Longton. Egerton Coll. 
Plenracantbus robustus, Davis '. 
1880. Pleuracanthns robustus, J. W. Davis, Quart. Joum. 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. 4' Loe. Middle Coal-Measures : Yorkshire. 
P. 1177, P. 1180. Five incomplete specimens ; Tingley. 
Presented by the Earl of Enniskillen, 1882. 
21423. Four small spines, doubtfully associated with this species ; 
Coal-Measures, Carluke, Lanarkshire. Purchased, 1847. 
* It is not improbable that the so-called Compsacanthus triangularis is 
founded upon an abraded spine of thb species (J. W. Davis, Quart. Journ. 
Geol. Soc. voL xxxvi. (18S01 p. 62, woodc.). 
