116 BRITISH PALAZOZOIC FOSSILS. [ EcHinopERMATA. 
Potypora VERRUCOSA (M‘Coy). 
Ref.—M°Coy, Syn. Carb. Foss. Irel. t. 29. f. 6. 
Sp. Ch.—Interstices straight, round, nearly half a line wide, equal, bifurcating rarely at less than three 
or four lines, (often upwards of an inch without branching); obverse with four alternating rows of pro- 
minent wart-like pores, about eight or ten in each row to the length of a fenestrule, intervals between the 
pores marked with waving longitudinal strie; reverse nearly smooth; dissepiments thin, distant; fene- 
strules regular, rectangular, oblong, sub-equal, about five times longer than wide, slightly wider than the 
interstices (three in two lines measured transversely) and about two and a half lines long. 
This is the only species of the genus in which I have seen prominent-edged pores. 
Rare in the carboniferous limestone of Derbyshire; the original Irish locality was the lower limestone 
of Kildare. 
6th Class. ECHINODERMATA. See page 51. 
ist Order CrinorpEa. See page 52. 
Genus. POTERIOCRINUS (M//l.) restricted by Aust. 
Gen. Char.—Column and alimentary canal round, with round axillary side arms; cup conical, formed of 
pelvis, one row of primary and one row of secondary radials, and an irregular group of three interradials on 
one side; pelvis of five large pentagonal plates, their bases resting on the upper columnar joint; alternating 
above these are two obscurely heptagonal and three hexagonal primary radials, alternating over which, are five 
pentagonal Ist secondary radials (scapulze), between two of which, are two or three small, interradial plates ; free 
rays composed of a few of the secondary radials (arm-joints) as wide, or nearly so, as the Ist (or scapule). 
Prof. Phillips and some other authors notice in their descriptions of this genus the existence of a very 
minute, pentagonal, tripartite pelvis, entirely concealed within the columnar articulation marking the bases of 
the five plates above considered ‘pelvic’: I have never seen any trace of this supposed, very abnormal, 
pelvis, and I can state that it does not exist in the Poteriocrinus impressus (Phil.), in which I have seen the base 
clearly exhibited with the five divisional lines extending to the minute alimentary opening. 
POTERIOCRINUS GRANULOSUS (Phill.) 
Ref.—Phill. Geol. York. Vol. II. t. 4. f. 2. 4, 8, 9, 10. 
Sp. Ch.—Cup obtusely conical, one-third wider than long to the edge of 1st secondary radials (scapule) ; 
pelvis small, pentagonal of five pentagonal plates, twice as wide as long, excavated and radiated at their base to 
form part of the columnar attachment; between and above these are inserted five pentagonal (or obscurely 
hexagonal) Ist primary radials, one-third wider than long; alternating over these are five pentagonal Ist 
secondary radials (scapulee) twice as wide as long; all the plates nearly flat and closely covered with fine granules. 
Length of cup about half an inch. 
One of the primary radials is hexagonal and has one of its upper sides so long and nearly horizontal that it 
seems to support one of the scapulee or secondary radials, and on its shorter side it has the long irregular hex- 
agonal Ist interradial plate, supporting two small lengthened 2nd interradials. 
Position and Locality—Common in the carboniferous limestone of Derbyshire. 
