ZooruyrA.] LOWER PALAZOZOIC RADIATA. 43 
The substance of this species seems exceedingly thin; it is easily distinguished by the very slender 
distinctly forking, distant, radiating ridges, with the intervening spaces smooth or nearly so, the margin of one 
specimen shewing doubtful traces, at one point of the margin, of intermediate strize; the distance between the 
ridges is about ten or fifteen times their thickness. 
Position and Locality.—Not uncommon in the black schists of Dinas Bran, Llangollen. 
SPONGARIUM INTERLINEATUM (J/‘Coy). Pl. 1. B. fig. 14. 
Ref.—M°Coy, Ann. Nat. Hist. 2nd Series, Vol. VI. p. 281. 
Sp. Ch.—Broad oval, usual proportion of width to length as 85 to 100; marked with very strong con- 
centric undulations; radiating ridges very numerous, straight, slender, simple, of unequal lengths, averaging 
with considerable regularity half a line apart; intervening spaces finely striated radiatingly ; long diameter 
varying from seven lines to one inch three lines. 
This species is easily distinguished from the S. Hdwardsi (Murch.) by having considerably more than 
double the number of radiating ridges; they have never been seen to dichotomise, but retain their compa- 
ratively near approximation by the intercalation of similar, straight, shorter ridges towards the circumference ; 
the substance also appears stronger and is more strongly wrinkled concentrically, the small radiating strize 
between the larger ridges are very characteristic. 
One very obscure specimen, apparently of this species, measures two inches in its long diameter, the 
distance between the main ridges is about four times their thickness. 
Position and Locality—Abundant in the green micaceous quartzite of the Upper Ludlow at Benson 
Knot, Kendal; Brigsteer and Scalthwaite Rigg, Kendal, Westmoreland. 
Explanation of Figures—P\. 1. B. fig. 14. From the Upper Ludlow rock of Kendal, natural size — 
Fig. 14a. Do. Portion of exterior surface magnified two diameters, shewing the fine strie between the 
larger radii. 
SPONGARIUM INTERRUPTUM (M/°Coy). Pl. 1. B. fig. 16, 17. 
Ref —M°Coy, Ann. Nat. Hist. 2nd Series, Vol. VI. p. 282. 
Sp. Ch.—Elliptical, proportion of width to length about 85 to 100, convex below or externally, concave 
above or internally ; interior smooth, or marked with faint concentric wrinkles; exterior rugged with coarse 
concentric undulations, and its entire surface marked with sharp, sub-alternate, thread-like strice, five or six 
in one line ; some of which rise at regular intervals into short, very thick, sub-angular, radiating ridges inter- 
rupted by the concentric wrinkles and not regularly resumed. Average length one inch. 
The sharp alternately large and small striee, and the short irregular interrupted ridges or elongate 
tubercles produced by the irregular prominence of some of the ridges, distinguish this species readily from 
the others. ‘Two of the specimens are of great interest, one shewing the attachment of the base half round 
a bit, apparently, of an Orthoceratite; the other shewing, for the first time, the thickness of the substance 
to be about one sixth of a line, and shewing the unradiated inner concave surface, and the impression of 
a part of the peculiarly radiated exterior. 
Position and Locality—Rare in the green micaceous quartzite (Upper Ludlow) of Spital, Kendal, 
Westmoreland. 
Explanation of Figures—P|. 1. B. fig. 16. Natural size, from the Upper Ludlow rock of Kendal, 
shewing the attachment of the base, and peculiar interrupted markings.—Fig. 16a. Do. Portion of surface 
magnified two diameters.—Fig. 17. Do. Portion of specimen shewing the upper concave, concentrically 
wrinkled, surface, and at the upper corner a portion broken away, leaving the impression of the radiated 
exterior on the supporting matrix. 
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