16 BRITISH PALAZOZOIC FOSSILS. [Zoopuyra. 
less than three and often five between each of the cell-tubes). Mr Lonsdale’s reference (Sil. Syst.) of this 
coral to the Devonian P. pyriformis (Blainv.) is universally admitted to be injudicious. The two specific 
names above quoted from M. d’Orbigny, are merely given as names to the separate figures of this species 
in the Silurian System, without definitions; and I believe there is no specific distinction to be drawn between 
them. 
Position and Locality—Abundant in the Wenlock limestone near Aymestry, Herefordshire ; calcareous 
shales, Wenlock, Shropshire; Malverns; Coniston limestone of Long Sleddale, Westmoreland. A doubtful 
variety rare in Coniston limestone at Coniston Water-Head, Lancashire, and in the impure calcareous 
schists of Applethwaite Common, Westmoreland. 
Var. a. SUBTUBULATA (M/°Coy). PI. 1. C. fig. 2. 
Sp. Ch.—Corallum composed of radiating thick-walled persistent cylindrical tubes (often exhibited 
separately in the weathered yertical section), with the usual diameter of half a line, generally more than 
their diameter apart, crenulations and radiating lamelle very small and indistinctly marked; horizontal 
diaphragms strong, flat, two interdiaphragmatz equal to the diameter of the tube; interstitial spaces filled 
with very numerous, minute, capillary, polygonal tubes, the spaces between the diaphragms of which are 
slightly less than their diameters. 
In the frequency with which the cylindrical tubes are exhibited in weathered specimens distinctly 
separated from the mass, as well as the distance of the diaphragms apart, this species resembles the 
P. tubulata (Lonsd. Sp.), from which it is distinguished by the distance of the tubes apart, the nearly 
obsolete crenulations or radiation of their interior, and by the intervening space being filled with very 
numerous capillary prismatic tubes; in the last two characters it approximates to the P. interstincta, from 
which it is distinguished by the greater strength of the walls of the tubes, their small diameter and greater 
distance from each other, and more distant diaphragms; but as I have noted a small-tubed variety of the 
P. interstincta from Malvern, apparently in some degree intermediate, I only propose this at present as a 
strongly-marked variety of that species. 
Position and Locality—Oceurs occasionally in the Coniston limestone of Coniston Water-Head, Lan- 
eashire, and Llansantfraid, Denbighshire; Wenlock limestone, near Aymestry, Herefordshire. 
Explanation of Figures—Plate 1. C. fig. 2. Portion of weathered mass, natural size, from Coniston 
Water, shewing the main tubes projecting in one part.—Fig. 2a. Portion of ditto magnified six diameters, 
shewing the weathered appearance of the base of the lamelliferous tubes and the interstitial tubules.— 
Fig. 24. Portion of weathered mass magnified six diameters, shewing the projecting lamelliferous tubes, 
and intervening polygonal tubuli. 
PALHOPORA MEGASTOMA (M‘Coy). Pl. 1. C. fig. 4. 
Ref. and Syn.— Porites megastoma (M°Coy). Syn. Sil. Fos. of Ireland, t. 4, f. 14. 
Sp. Ch.—Corallum forming large hemispherical or irregular masses; base concentrically rugose ; 
stellular tubes averaging a line and half in diameter, with strong radiating lamelle about one-fourth the 
diameter of the tube in length; diaphragms strong, apparently pitted on their upper surface ; interstices of 
small polygonal vertical tubes, (averaging five in one line); usually about three interstitial tubes in a line 
between the lamelliferous tubes, which are in most cases rather less than half their diameter apart. 
This species seems to replace in abundance, in the lower Silurian beds, the so-called P. pyriformis 
(P. interstincta) of the Wenlock Rocks. It is distinguished from that species by the great size of the stel- 
lular tubes, which vary in the adult from one and half to nearly two lines in diameter, and the great 
proportional strength of the walls, which frequently causes them, like P. twbulata, to stand up as separate 
suleated columns in the weathered examples; the radiating lamelle are also much more strongly marked in 
the P. megastoma, which serves to distinguish the dwarf examples in which the tubes may occasionally sink 
to near the same diameter; the transverse diaphragms seem irregularly pitted on their upper surface and 
to be smooth below. 
