580 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Genus COLPOPHYLLIA Milne Edwards and Haime." 



Polyps verrucose, incompletely separated, giving' rise to broad, continuous, flexuous, discal and 

 columnar systems, and producing massive, light, flattened or slightly convex colonies, fixed by a broad 

 or pedunculate base. Column wall united with that of contiguous rows along a broad common plateau, 

 having a restricted, perithecal continuation of the gastro-ccelomic cavity and mesenteries, better 

 developed at the periphery of the colony; in retraction the column wall folds over the tentacular zone 

 and covers the margin of the disk; no sphincter. Tentacles in two, alternating, slightly entacmaeous 

 rows, entoccelic and exoccelic. Disk with numerous oral apertures, variable in size; stomodaeal walls 

 deeply ridged. 



Mesenteries acyclic and mainly complete, with occasional incomplete developing pairs; arranged in 

 irregular stomodaeal systems; all filamentiferous; directives absent, except in larval polyps; increase by 

 irregular addition of unilateral pairs; partly extrusible. Septal invaginations mainly entoccelic, uniform 

 when fully developed, not all meeting in the middle. 



Asexual reproduction by incomplete fission. 



Example. — Colpopkyllia gyrosa (Ell. & Sol.). 



COLPOPHYLLIA GYROSA (Ellis & Solander). 

 (PI. XXII, fig. 148.) 



External characters. — The species occurs somewhat sparingly in Kingston Harbor and on 

 the reefs outside, the colonies forming massive, hemispherical or irregular blocks on the sea floor, 

 which are usually easily detached. The broad discal valleys, thick thecal ridges, and strongly 

 developed septa give the species a coarse appearance in situ compared with most other corals. 

 The distance from the apex of one thecal ridge to another is variable, but is usually between 

 2 and 3 cm. The valleys are sinuous, never extending for more than a short distance in a 

 straight line, and usually sloping toward the periphery; a very shallow depression also occurs 

 along the middle of the thecal ridges. A broad edge-zone is found around the margin of tha 

 colony, and also a narrow extracalicular continuation of the coelomic cavit}' and mesenteries 

 along the contiguous thecal rows. 



The polyps ai - e very rarely seen in their expanded condition. During the ordinary 

 condition of retraction the upper margin of the column wall is withdrawn within the calice for 

 about half the height of the thecal ridges, and appears almost in continuity with the disk, the 

 tentacles being completely hidden by it. The wall is divided into longitudinal ridges and furrows, 

 in correspondence with the internal septa and mesenteries, and the marginal teeth on the septa 

 give an external verrucose appearance to the walls. In some places the longitudinal ridges are 

 all equal, but in most a much smaller verrucose ridge alternates with the larger, though never 

 for more than three or four consecutive pairs. 



In the retracted condition of the polyps the tentacles are entirely hidden under the 

 overfolding column wall, and have not been seen fully extended. Microscopic examination 

 indicates the presence of lateral nematocyst areas and of a large terminal battery, so that in all 

 probability they closely resemble the tentacles of Manicina. 



The disk is radiately divided around the oral apertures by the internal mesenteries and septa, 

 or, where the valleys are long and straight, the divisions become more parallel; verrucse occur 

 over the areas corresponding with the septa, but not all the rows extend as far as the stomodseum. 



The oral apertures are oval or round when open, slitdike when closed, the longer diameter 

 being along the length of the disk. The apertures are from 1 to 2 cm. apart. The stomodasal 

 walls are provided with strongly marked vertical ridges, five to ten on each side, and in the living 

 condition they appear intensely white against the darker valleys. 



The general coloration of the polyps in ■situ is light or dark brown. Examined more closely, 

 the column wall is brown with grayish verrucal rows. The disk may exhibit a bright, iridescent 



" "Colony massive, light and fragile, with a broad base, or pedunculate. Corallites united by their costie, the 

 walls never fusing at the calicular surface, where they are very slender. Calicinal valleys moderately long, flexuous, 

 large, deep, with the calicinal centers more or less distinct. Columella rudimentary or none. Septa excessively 

 thin, long, slightly exsert, and striated laterally; their free margin is delicately toothed and slightly excised near the 

 middle. The common plateau has small lamellar costse, broken up by dentations which are horizontal." (Duncan, 

 1885, p. 94. ) 



