MR. H. N. MOSELEY OR THE STRUCTURE OF THE STYLASTERIDTE. 4 77 
sporadic in disposition. Dactylopores with a more or less rudimentary style afhxed 
to those parts of their walls which are outermost in the systems. Gastropores, simple 
tubular, with a brush-like style. Ampullae sometimes prominent, sometimes scarcely 
showing at the surface. Dactylozooids attached by elongate bases to the sides ol 
them pores occupied by the styles ; partly retracted within the pores, partly bent 
upwards when at rest within the wide pore mouths. Gastrozooids dome-like in 
shape, with twelve tentacles and numerous basal canals. Gonangia in male stocks 
containing two or three ovoid gonophores with club-shaped spadices. Structure of 
gonophores of female stocks unknown. 
Genus 7. Stylaster, Gray. — Corallum arborescent usually llabelhform. Pores in 
regular cyclo-systems only. A strong tendency to the development of these cyclo- 
systems on the lateral margins of the branches only. Cyclo-systems arising from one 
another by alternate gemmation. Dactylopores and zooids as in Allopora. Ampullae 
usually prominent on both faces of the flabellum. Gastrozooids cylindrical, with 
numerous basal canals and eight tentacles. Gonophores of male stocks as in Allopora. 
Structure of females unknown. 
Genus 8. Astylus, gen. nov., H. N. M. — Corallum forming a small and delicate 
flabellum. Pores in regular cyclo-systems, all placed on one face of the flabellum. 
Cyclo-systems forming cylindrical masses prominent from the branches, and with then- 
axes directed at right angles to the plane of the flabellum. Style absent in both kinds 
of pores. Gastropores divided into two chambers, an upper and lower, by a constriction 
of then- walls. Opening between the chambers rendered horseshoe-shaped by the pro- 
jection across it, in the direction of the tips of the branches, from that side of its margin 
placed nearest the bases of the branches, of a tongue-like excrescence. Ampullae in 
the male stocks in a ring around the cyclo-system masses ; none scattered on the 
branches. Dactylozooids, when at rest, doubled down within the upper chambers of 
the gastropores. Gastrozooids flask-shaped, devoid of tentacles, with numerous basal 
canals. Gonangia in the male stocks containing a central mass of cells, from the 
surface of which are developed as buds numerous pedicellate lobular sacs, in which the 
spermatozoa are produced. Female stocks unknown. 
Genus 9. Cryptolidia , M. Edwards and Haime. — Corallum closely resembling that 
of Astylus in all respects, excepting that the cyclo-system masses are not so promi- 
nent, that the opening between the upper and lower chambers of the gastropores is 
circular in outline, and that a lid-like lamina of calcareous matter is directed horizon- 
tally across the mouths of all the cyclo-systems. The lids are supported on stout 
columns arising from the margins of the cyclo-systems and inclined over them. They 
spring from the sides of the systems nearest the bases of the branches, and are 
directed towards the tips of the branches. In female stocks only a single ampulla 
and gonangium developed in relation with each cyclo-system. No ampul he on the 
connecting branches. In the males several ampullae in the walls of each cyclo-system. 
Soft structures as in Astylus. In female stocks numerous gonophores present in each 
