MR. H. N. MOSELEY ON THE STRUCTURE OE THE STYLASTERIDHC. 
distance into the axes of the spines, beyond the slit-like commencement of the grooves. 
The grooves are the cavities which are occupied by dactylozooids — are, in fact, the 
dactylopores, which are here excavated within long projecting spines, and are widely 
open on one side for nearly their entire length. The small continuation of the groove 
within the axis of each spine represents the normal dactylopore. 
Two kinds of dactylopores occur in the present form : the larger ones already 
described, and much smaller pores, which are mostly placed on the bases of the 
spinous processes, but occur also more sparingly on the general surface of the stem. 
These smaller pores often have the sides of their mouths slightly raised above the 
surface which they perforate. 
The main surface of the stems and branches of the corallum is grooved by short 
canals, which are just open to the surface and run short courses, being never much 
branched and usually crooked (Plate 35, fig. 4). These channels correspond with those 
described as occurring in Errina, and are occupied in the recent condition of the 
coral by the most superficial reticulations of the coenosarcal meshwork. 
Lying in deep depressions between the bases of the spinous projections are the 
gastropores, which are deep pits with circular mouths, at the margins of which 
dactylopores .of the smaller kind frequently open. The gastropores are provided with 
styles, which are very deeply situate and have brush-like tips, and are much like those 
of Sporadopora, but not so elaborately branched. The substance of the corallum of 
Spinipora echinata is hard and compact in structure, and white. 
Soft Structures of Spinipora echinata. (Plate 38.) 
Coenosarc. — The coenosarc consists of the usual reticulation of canals (Plate 38), offsets 
of which pass into and ramify within the dactylopore spines as at B, Plate 38. There 
is a well-developed continuous surface layer of ectoderm, which invests the spinous 
processes and entire surface of the coral, and feebly maintains, in decalcified specimens, 
the form of the corallum. The layer is, as in other genera of the family, continued into 
the pores of the corallum to form the sacs of the zooids. The nematocysts are closely 
similar to those of Errina. 
Dactylozooids. — These are of two forms, larger and smaller. The larger dactylozooids 
are attached by elongate bases along nearly the whole lengths of the bottoms of the 
groove-like dactylopore cavities. The ends of these elongate bases nearest the coral 
stems- assume a cylindrical form, and are continued into the pore-like prolongations of 
the grooves, to become continuous with canals of the coenosarcal meshwork. In 
Plate 38, two dactylopore spines, B B, are shown as cut open in order to exhibit this 
arrangement. The pore-like continuations of the dactylopore grooves are fined by 
continuations of the surface layer representing the zooid sacs. The free parts of the 
dactylozooids spring from the elongate attached parts not far from the tips of the 
spines. In the contracted condition they appear as short, stout, bluntly conical bodies, 
