MATTHAI— RECENT COLONIAL ASTR^ID^ 63 



Corallum. Perithecal vesicles slightly larger than in G. fascicularis ; usually closed 

 on surface. Corallites oval or circular, much smaller than in last species, projecting above 

 peritheca up to 3"5 mm., of even diameter or somewhat increasing from calicular opening 

 to peritheca, up to 5 mm. apart, usually 3 mm., not so diverging as in last. Walls of about 

 same thickness. Calices with diameters 4x3 mm., depth 1"75 mm. 



Septa in four orders, the first three complete, the fourth incom23lete, maximum 

 number 13, hence most of the tertiaries exocoelic ; septa exsert vertically, sides rough, 

 edges entire sharp, primaries usually thicker than secondaries, both exsert to 1'5 mm., 

 swollen in thecse and meeting columella. Tertiaries with edges free and exsert to 1'5 mm. 

 Oostse smooth, seen as sharp ridges along almost the whole projecting part of corallite- 

 wall. Columella distinct, circular or oval in outline, about 75 mm. broad, sometimes 

 laterally compressed and septa meeting above it. Budding from any part of peritheca. 



Polyps. (1) Size small, corresponding with corallites. (2) Entocoelic tentacles 

 much less differentiated than exocoelic ; terminal batteries with loosely arranged nemato- 

 cysts, not swollen ; sub-terminal batteries not defined, with numerous nematocysts. 

 (3) Exocoelic tentacle with up to about twelve sub-terminal batteries. (4) Quaternary 

 couples of mesenteries absent. (5) Ectoderm of outer wall of edge-zone not more than 

 half the thickness of oral-disc ectoderm. (6) "Ovoid bodies" fewer than in G. fasci- 

 cularis. (7) Algae much more abundant than in G. fascicularis. 



Remarks. A. Polyps. The tertiary cycle of mesenteries was incomplete, the 

 couples being 6, 3 and 1 in the three polyps examined. One of the polyps was abnormal 

 in possessing a third couple of directives. The exocoelic tentacles are somewhat bluntly 

 pointed. The primary septa press against the stomodgeum near the enterostome, 

 greatly distorting its wall and almost occluding its lumen ; if this means an imperfect 

 functional capacity, as I am disposed to suggest, it is correlated with a great abundance 

 of algse. The ectoderm of the oral-disc is thick, with numerous nematocysts I and a few 

 of 11. Ovoid bodies are scarce in both the oral-disc and edge-zone ; some of them are 

 narrower than in G. fascicularis, with .no central core but with traces of a spiral 

 suggesting degenerate nematocysts I. In the terminal batteries of exoccslic tentacles, 

 nematocysts II h are less numerous than in the last species. Ovoid bodies are present in 

 the sub-terminal batteries. The stoniodaeal ridges are not so thick as in the last species. 

 In the coils of the mesenterial filaments nematocysts I are more numerous. Entocoelic 

 pleats are broader and thicker than in G. fascicularis, and tend to arise in groups of 

 three or four, the pleats of each group often fusing at their bases to form thick compound 

 ridges. The endoderm in the oral-disc is thicker than in the last species, and is massed 

 with algge ; it is much thinner in the outer wall of the edge-zone, considerably thickened 

 in the tentacles owing to vacuolation, and filled with algge, occluding the lumen in the 

 region of the terminal batteries of the exocoelic tentacles. The mesenterial endoderm . 

 is somewhat thicker on the exocoelic side where algae are massed together. 



The polyps examined were ripe females. The eggs are carried in a single row on the 

 exocoelic side of every mesentery, in transverse section each egg almost fitting the 

 exocoele. The appearance of a double row of eggs is sometimes presented, owing to 

 either the overlapping of neighbouring eggs or to the eggs of adjacent mesenteries being 



