Zooruyra.| UPPER PALAZOZOIC RADIATA. 111 
very delicate lamin radiate to ‘the adjoining ones, generally without interruption, the radii connected by 
numerous small transverse vesicular plates; vertical section, centres forming nearly vertical and subparallel 
cylindrical tubes, with close concave transverse septa, the tubes connected by exceedingly fine, uniform, 
cellulose structure, which seems formed of small depressed cells, arranged nearly in horizontal layers, with 
a double curve conforming to the projections of the surface; horizontal section, shews the tubular centres 
connected by a minute uniform cellular structure with a scarcely appreciable radiation. 
This strongly resembles the Wenlock limestone, so-called Acervularia Baltica of the ‘Silurian System.’ 
Position and Locality —Rare in the carboniferous limestone of Derbyshire. 
Explanation of Figures—P\. 8. B. fig. 8. Portion’ of large mass, natural size, exhibiting the terminal 
weathered stars, and rough vertical section shewing the thin layers of vesicular tissue, extending with a double 
curve from one centre to another, and the transverse cellular plates filling the central tubes; also, the not 
uncommon appearance of the axis weathering as a separate cylinder, vertically suleated by the origins of 
the radiating lamelle.—Fig.8a. Do. Horizontal and vertical sections of portion of a small specimen 
magnified three diameters, the former shewing the plain centres and the uninterrupted passage of the radiating 
lamellee from one centre to another, connected by the vesicular plates. 
Subfamily. ASTRAINE. See page 37. 
Astrma (Palastrea) carBonaRta (M°Coy). PI. 3. A. fig. 7. and 3. B. fig. 1. 
Ref.—MCoy, Ann. Nat. Hist. 2nd Series, Vol. III. p. 125. 
Sp. Ch.—Corallum forming very large masses; terminal stars from nine lines to an inch and a half 
in diameter, obscurely pentagonal, bounded by narrow, rounded, or obscurely angular cellular spaces (no 
simple divisional walls), having from one hundred and seven to one hundred and thirty thin, jagged, 
radiating lamelle, which descend to form an oval or circular cup, and one half of which rise again to 
form an oyal central boss, by the edge being produced into an abrupt paliform lobe (not distinguishable 
from the lamella); in the centre the lamellae become indistinctly blended: vertical section shews the 
uninterrupted passage of the loose vesicular tissue, conforming to the shape of the terminal cup, in gentle 
curves from star to star; a very small space directly under the centre of each star, having the vesicular 
structure almost transverse; horizontal section shews the alternately long and short radiating lamellz, 
connected (except in a small space near the centre) by fine transverse vesicular plates, and the former 
obscurely blended at the centre (no axis), and the irregular cellular structure intervening between the 
adjacent stars. 
This magnificent species is the only apparently true Asfrwa I have yet seen from the Paleozoic 
rocks; the numerous Paleozoic corals described under this generic title by British and foreign authors, 
belong, for the most part, to Strombodes, Nematophyllum, Acervularia, &c.; often transversely septate in 
the middle and having solid polygonal divisional walls to the stars—characters completely at variance with 
those of the recent and mesozoic Astrea, and indicating important differences in the animals and mode 
of increase. I propose the subgeneric title Palastrwa for this species, as it seems to differ from the newer 
types in the vast number and tenuity of the lamelle, and the great cylindrical boss in the cup from the 
unthickened pali-form lobes of the larger lamellz. 
Position and Locality—Abundant in some parts of the carboniferous limestone near Bakewell, Derby- 
shire; more rare in the same formation at Corwen. 
Explanation of Figures.—P). 3. A. fig.7. Part of mass, natural size from Derbyshire, shewing weathered 
terminal cells of small stars at the right-hand corner. Ditto, worn at the left-hand——Fig. 7a. Do. 
Part of same mass shewing at top horizontal sections of one large star, magnified two diameters, and 
portions of two others shewing the vesicular character of the spaces between them, the irregular centres, 
numerous radiating lamellze and connecting vesicular plates; the lower portions of the figure shew a ver- 
tical section, the vertical lines in the left half being the ends of the radiating lamella, the vesicular 
structure in the right half shewing the uninterrupted passage of this texture from the interspace to the 
centre.—Pl. 3. B. f. 1. Do. ‘Terminal stars, natural size, from Derbyshire. 
