100 BRITISH PALA®OZOIC FOSSILS. [Zoopuyra. 
Position and Locality—Forms large depressed, convex masses, ten inches or more in diameter, in the 
carboniferous limestone of Kendal. 
Explanation of Figures—P1. 3. B. fig. 3. Portion of large mass, natural size, shewing the weathered 
terminal stars (a peculiarity of weathering, shewing the solid walls and axis as impressed lines), the very 
slight convexity of the inner and outer areas, and the occasional circular young buds developed in the corners 
of some of the stars.—Fig. 3a. Do. Vertical section magnified three diameters, shewing the characters of 
the axis and the vesicular plates of both areas, together with the supposed original form of the star deduced from 
the direction of the vesicular plates of both areas.—Fig. 36. Do. Horizontal section magnified three 
diameters. 
Genus. STYLAXIS (M°Coy). 
Ref —M ‘Coy, Ann. Nat. Hist. 2nd Series, Vol. ITI. p. 119. 
Gen. Char.—Corallum composed of adjacent polygonal prismatic, easily separable tubes, internally 
divided into three areas: vertical section, first, a thin, flat, straight axis; second, a broad inner area, 
composed of numerous curved vesicular plates in irregular rows, converging upwards to the axis; third, 
an outer area on each side, composed of smaller and more curved vesicular plates, in rows inclining 
obliquely upwards and outwards: horizontal section, displaying the central flat axis, surrounded by radiating 
lamellee extending from the walls, and connected in the outer area by numerous transverse vesicular plates: 
additional columns, produced by a bipartite division of the parent stem, parallel to one of its faces: 
polyps distinetly separated above. 
The corals of this genus bear precisely the same relation to Nematophyllum that Stylastrea (Lonsd.) 
does to Lithostrotion of the same writer (Strombodes), with regard to their mode of development, that is 
to say, in Nematophyllum, as in Strombodes, the increase is by circular buds developed within the walls 
of the parent stem, the polygonal walls being gradually perfected by the joint labour of adjacent polyps, 
which it is inferred from their mode of growth had a community of existence and organic union at the 
surface, and from the same cause the columns haye no outer surface to exhibit in a rough fracture, but 
break through the middle rather than separate one from another. In the Stylawis, however, as in the 
Stylastrea, the new columns are produced by a sudden splitting of one of the columns into two, the 
divisional lines commencing along the middle of one face and going directly across to the opposite face, 
distinctly separating the young foursided column at once by a double plated, rectilinear boundary-wall, 
parallel with one of the faces; the external striz of the old column being traceable upwards into the 
young one which may probably be viewed as a compressed branch from a lateral bud. The columns are 
easily separable one from another in the rough fracture, and the polyps are inferred to have been distinct 
from each other, and each to have constructed independently its own boundary-wall. 
StyLaAxis Freminent (A/°Coy). Pl. 3. A. fig. 3. 
Lief —MCoy, Ann. Nat. Hist. 2nd Series, Vol. III. p. 121. 
Sp. Ch.—Corallum of very long, prismatic, generally hexagonal, easily separable tubes, averaging three 
lines in diameter; outer surface strongly striated longitudinally, and marked with direct transverse rugosities 
of growth; bipartite division of the columns frequent; vertical section, exhibiting the thin flat axis, sur- 
rounded by an inner zone of small, slightly curved, interstitial plates, inclining downwards and outwards 
from the axis, forming on each side a row of nearly simple oblique cells; outer zone of small vesicular, 
much curved plates, inclined in an opposite direction, or upwards and outwards, four or five in a row: 
horizontal section, axis thin, half a line wide, surrounded by about forty-three thin, radiating lamelle from 
the walls, half of which only reach half way; numerous small, thin, transverse, connecting plates between 
the lamellze in the outer zone. 
The bipartite mode of division of the column is frequently and easily observed in this species, which 
commonly forms large masses. It greatly resembles, externally, the Stylastrea basaltiformis, but is easily 
