MATTHAI— EECENT COLONIAL ASTR^HD^ 97 



In the ectoderm of the oral-disc iiematocysts I are more frequently found than in the 

 previous species, each with a spiral of about 20 turns ; type II are rarely present. 



Filaments are attached to the principal mesenteries and to the wider subsidiary ones ; 

 they are almost circular in section. A few nematocysts I are present in their straight 

 regions, while lib are frequently found in their coils. Below the stomodseal region of 

 polyp the entocoelic pleats extend over almost the entire width of the mesentery, becoming 

 broader towards the skeletal attachments. The endoderm of the oral-disc is never thicker 

 than the overlying ectoderm, in parts only half the thickness of the latter ; it has a 

 columnar facies as the nuclei are aggregated along its margin where algse never occur ; 

 the thin circular layer of muscle-fibres is well seen. Both tentacular and stomodseal 

 endoderm are thin with few algae. Only in some of the mesenteries is the endoderm 

 swollen behind the filaments, where occasionally nematocysts II are seen. The com- 

 parative thinness of the endoderm and the scarcity of algse are distinctive of this species. 

 Ova were present in some of the principal and subsidiary mesenteries in one or two 

 longitudinal rows. 



Number of polyps examined, three, from a colony from Hulule, Maldives. 



B. Corallum. In the Salomon specimens, as also in Klunzinger's example of 

 Prionastrcea pentagona, up to 5 or 6 of the principal septa tend to become thicker, broader 

 and more exsert than the others ; this is particularly evident in some elongated corallites 

 and perhaps shows where division is ultimately to take place. This process is carried 

 further in Gardiner's type of Favia adduensis, in which many of the corallites appear 

 either elongated or distorted, in all probability due to delayed fission, the diameters 

 of the calices in such cases being about 6 — 7 and 4 mm. with 12 — 14 septa meeting the 

 columella. The latter is a well-formed structure, either closely spongy or quite compact. 

 The corallites towards the edges of this specimen are not elongated and closely resemble 

 those of the Maldive examples of the present species. 



Ehrenberg's type of Astrcea melicerum consists of three incrusting bits on a gastropod 

 shell (PL 36, fig. 4); though somewhat defaced their specific characters may still be 

 recognised. Similar to this is Klunzinger's small figured example of Prionastrcea 

 pe7itagona. 



In the Paris Museum there are two large specimens named PrionastrcBa gihhosissima, 

 Ed. and H., measuring 22 x 16 x 14 cm. (loc?) and 38 x 25 x 30 cm. (Bed Sea), the former 

 probably the type. Milne Edwards and Haime have also referred two specimens to 

 PrionastroBa melicerum, one small from Red Sea, the other large (20x19x19 cm.) 

 and with low humps from Seychelles (both re-named PrionastrcBa pentagona by 

 Klunzinger) ; in the latter the calices are about 5 mm. in depth, columella distinct in 

 most corallites, towards edges calices larger up to 6 mm. in diameter, columella rudimentary 

 and paliform lobes conspicuous. Identical with these is another example from Seychelles 

 named Prionastrcea abdita, later referred by Klunzinger to PrionastrcBa pentagona and 

 also Milne Edwards and Haime's large figured type of Goniastrcea rudis. A small piece 

 named Astrangia asiatica, Mich., in Michelin's collection from East Indies, also belongs to 

 F. pentagona. 



From Quelch's description of his new species Goniastrcea laxa from Api, New 

 SECOND SERIES— ZOOLOGY, VOL. XVIL 13 



