MATTHAI— RECENT COLONIAL ASTR^ID^ 93 



definitely hemispherical in transverse section ; in their straight regions nematocysts I are 

 less numerous than in F. favus, while in their coils types II and III occur, the latter 

 not in such large numbers as in F. favus. The endoderm stains brown when treated with 

 iron — heematoxylin and eosin, specially noticeably in the mesenteries. The goblet-shaped 

 vacuoles in the mesenterial endoderm are massed together as in Cyphastrea serailia. 

 Behind the filaments the endoderm is swollen to their thickness, the filaments and their 

 endodermal pads giving a characteristic appearance to the polyp in transverse section. 

 Below the stomodseal region of the polyp, the entocoelic pleats are better seen and extend 

 over the gTeater part of the width of the mesenteries. 



In two of the polyps sectioned large ova are present in all the mesenteries in one to 

 four longitudinal rows, with germ-cells in the endoderm surrounding them. In another 

 polyp a group of minute dark-stained bodies of unknown nature is present in the mesoglsea 

 of nearly every mesentery in a cavity near its skeletal attachment. 



Number of polyps examined, four, 2 from a mature $, Hulule, Maldives, 1 from a 

 specimen dredged off Salomon, 1 from a specimen from Ceylon. 



B. Corallum. In the Paris Museum PrionastrcBa abdita, Ed. and H., is represented 

 by four large specimens (three thin, the fourth somewhat thickened), probably from the 

 Indian Ocean. A large specimen from Batavia, Indian Ocean referred by these authors 

 to PrionastrcBa magnifica (Blain.) is similar to P. abdita, Ed. and H. PrionastrcBa 

 crassior, Ed. and H., is represented by two type specimens, the larger measuring 

 14x12 cm. , and PrionastrcBa obtusata, (Lam. ) by a smaU convex one from Tongatabou, 

 all three being of the thick type. Two small examples from Yanikoro referred by Milne 

 Edwards and Haime to PrionastrcBa sulfurea (Valen.) and another smaller one from 

 New Ireland to PrionastrcBa quoyi, Ed. and H., are perhaps also to be placed in this 

 species. 



Ehrenberg's example of Astrcsa abdita has dendroid hillocks with thin coraUites at 

 the top of the hillocks and thicker ones on the main stems (PL 35, fig. 2). Klunzinger's 

 original of PrionastrcBa gibbosa is only a small edition of the present species. Two worn- 

 out specimens referred by Ehrenberg to Astrcea pentagona, Ehrb. are quite unlike 

 Klunzinger's example of PrionastrcBa pentagona ; they resemble the present species more 

 than any other. 



EUis and Solander's figured type of Madrepora abdita (15x15x9 cm.) is in the 

 University Museum, Glasgow ; though much damaged, its resemblance to the abdita 

 specimens in Paris and Berlin is obvious. 



Quelch has referred two small specimens from Kandavu, Fiji, to PrionastrcBa Jlexuosa, 

 (Dana) and PrionastrcBa obtusata, Ed. and H., and two others from Amboina to Prion- 

 astrcBa quoyi, Ed. and H. ; these four resemble the thick variety of F. abdita. A fairly 

 large specimen assigned to PrionastrcBa rohusta (Dana) agrees with the thin type. 

 A small fragment from Banda, referred by the same author to Goniastrcea favistella 

 (Dana), is identical with Klunzinger's type of PrionastrcBa gibbosa. 



Localities. Maldives: Hulule (12); Addu (l from edge of W. reef); Goidu (5). 

 Minikoi (6). Kotuma (11). Chagos : Salomon (2); Egmont, (l). Singapore (2). Ceylon 

 (small specimens). Also from Tongatabou, ? Vanikoro and ? New Ireland (Milne Edwards 



