36 BRITISH PALAZOZOIC FOSSILS. [Zooruyra. 
38rd Family. ASTRAIDA. 
Corallum simple or compound, with an external imperforate epitheca to the general mass; usually 
increasing by disk budding or fission; ccenenchyme absent, or formed by the extension and union of the 
costze and their connecting vesicular plates, never compact ; base of the cells becoming uniformly reticulated 
by the addition of small numerous transverse vesicular plates, no synapticulz. 
Subfamilies :—1, Husmiline ; 2, Astreine. 
Ist Subfamily. EUSMILIN A. 
Lamelle with smooth, entire edges; coste plain; axis often solid. 
This subfamily is divided into the following sections - 
1 Sect. Simple, or composed of defined cells, arranged in lines, or in branching groups, and, when 
compound, usually increasing by fission. (Contaiming Cyathazxonia, Sc.) 
2 Sect. Compound, of gyrating lines of confluent, undefined cells; lamellze smooth-sided ; fissiparous. 
(Not occurring in Paleozoic rocks). 
3 Sect. Compound, massive; cells defined, not arranged in lines, connected by their walls and costal 
ecenenchyme. (Containing Sarcinula, Sc.) 
4 Sect. Compound, individuals tubular, distant, with distinct walls, united by an abundant spumous 
exotheea, the costze not prolonged; increase by lateral budding, not by fission. (This section scarcely differs 
from the third, but is not found in Paleozoic rocks). 
Genus. CYATHAXONIA (Mich.) as here defined. 
Gen. Char.—Corallum simple, conical, outer wall longitudinally suleated, thin; axis thick, solid, styli- 
form; radiating lamelle strong, extending from the axis to the outer wall; very few or no connecting 
vesicular plates, no diaphragms. 
This genus is not well defined by M. Michelin, and both he (Lconographie) and M. @Orbigny 
(Prodrome) seem to include under it the present types and the Clisiophyllie of Dana. As these latter 
types have been properly defined by Mr Dana, I propose to restrict Michelin’s name, to the corals pre- 
senting the above internal characters. They seem most allied in internal structure to some of the 
Eusmiline of MM. Edwards and Haime, such for example as Stylosmilia. 
CYATHAXONIA SILURIENSIS (A/°Coy). PI. 1. C. fig. 11. 
Ref.—M ‘Coy, Ann. Nat. Hist. 2nd Series, Vol. VI. p. 281. 
Sp. Ch.—Corallum elongate conic, about five lines long, and two lines in diameter at that height from 
the base; strong central axis nearly one-third of the diameter; sixteen or seventeen strong radiating 
lamellze, each extending from the axis to the outer wall, before reaching which it bifurcates, leaving a 
triangular interlamellar space about equal in width to the distance between the adjoining lamelle; surface 
coarsely ridged longitudinally, the sulci corresponding to the divided edges of the lamella, leaving one of 
the equal intervening ridges to correspond with each of the spaces between the individual lamelle, and 
between their divided edges. 
This is the only species of the genus I am aware of in the Silurian rocks. 
Position and Locality—Rare in the Upper Ludlow Rock of Underbarrow, Kendal, Westmoreland. 
Explanation of Figures—Plate 1. ©. fig. 11. Natural size from Upper Ludlow Rock of Underbarrow, 
Kendal.—Fig. 11 a. Do. Magnified three diameters, shewing the strong costie, very large axis, and thick 
radiating lamelle, most of them splitting as they reach the wall. 
Genus. SARCINULA (Lam.)* 
Gen. Char.—Corallum composed of vertical, cylindrical, strong-walled tubes, with internal tranyerse septa, 
bearing delicate, vertical, radiating lamellze meeting in the centre, where there is often a small styliform axis; 
* MM. Milne Edwards and J. Haime (Ann. des Sciences Nat. s.3, v.10, p. 211) make the following note on the 
