MATTHAI— RECENT COLONIAL ASTRiEID^ 95 



twenty-one subsidiary couples were present in the tentacular region, sixteen or seventeen 

 extended down into the stomodseal region. Numerous mucous vacuoles are present in the 

 ectoderm of the oral-disc. The endoderm of the latter is as thick as the ectoderm, with 

 closely packed algse. The tentacles have swollen terminal batteries with the usual 

 structure and four to six sub-terminal batteries ; nematocysts I have about forty turns 

 of the spiral. The tentacular endoderm is lobulated with numerous algse but is only about 

 half the thickness of the overlying ectoderm. The stomodseum is laterally compressed ; in 

 the lower halves of its ridges nematocysts III and I are frequently present, the former 

 more numerous than in any other species examined. Filaments are present on all the 

 mesenteries ; in their straight regions nematocysts I are of common occurrence ; in their 

 coils are numerous nematocysts II and III. The mesenterial endoderm has comparatively 

 few algse ; it is swollen behind the filaments to the size of the latter or even larger ; into 

 this the pleats do not extend. In transverse sections the entocoelic pleats have an unique 

 appearance owing to their great breadth and branching nature. No gonads were present 

 in any of the polyps. 



Number of polyps examined, four, 2 from a colony from Ceylon of var. 1, and 2 from 

 another colony from Ceylon of var. 2. 



B. Corallum. Milne Edwards and Haime's type of Favia hertkolleti is a large 

 specimen (24 X 17 X 17 cm.) from Seychelles in which inter-corallite grooves are usually 

 present (PI. 23, fig. 4); identical with this are some of my Ceylon specimens. Of the 

 eight examples referred by these authors to Frionastrcea halicora, three come under the 

 present species. Their type of FrionastrcBa australiensis has a meandering tendency 

 but the separate corallites resemble those of Favia hertholleti. The single small type 

 of Phymastrma valenciennesi (an edge of a colony, measuring 5 x 4'5 x 2 cm.) perhaps 

 belongs to the present species ; it has deep inter-corallite grooves and coarse septal sides 

 and may therefore be only an extreme case of var. 2, described above, but the principal 

 septa have long teeth near their union with the columella. 



One of Forskal's types of Madrepora favus (21 x 17x15 cm., PI. 22, fig. 7) has the 

 same facies as var. 1 of the present species. Quelch's type of PhymastroBa aspera is 

 a small fragment, with deep inter-corallite grooves, which in all probability belongs here. 



Localities. Seychelles (2). Aldabra (2). Ceylon (5) ; also broken ones from Point 

 Pedro, Nainitavoe and Delft. Also from the Red Sea (Milne Edwards and Haime and 

 ? Forskal), ? Australia (Milne Edwards and Haime), and Banda (Quelch). 



7. Fa via pentagona (Esper). (PL 10, fig. 5 ; 24, figs. 2—4 ; 36, fig. 4.) 



1797. Madrepora pentagona, Esper, Ports. Pflanz., p. 23, pi. 39, figs. 1 and 2. 



1834. Astrcea melicerum, Ehrenberg, Corall. roth. Meer., p. 96. 



1850. Prionastrea gibhosissima, Milne Edwards and Haime, Ann. Sci. Nat., Zool., 3'= ser., xii, p. 133. 



1850. Gonidstrea rudis, Milne Edwards and Haime, Ann. Sci. Nat., Zool., 3"^ ser., xii, p. 161. 



1857. Goniastrcea rudis, Milne Edwards and Haime, Hist. Nat. Corall., ii, p. 445, pi. D5, fig. 5. 



1857. Prionastrcea melicerum, Milne Edwards and Haime, Hist. Nat. Corall., ii, p. 521. 



1877. Plesiastrcea haecheli, Brilggemann, Abh. Ver. Bremen, v, pp. 395 — 400. 



1879. Prionastrcea pentagona, Klunzinger, Korall. Roth. Meer., iii, p. 41, pi. 4, fig. 11 (non Astrcea pentagona, 



Ehrenberg). 



1886. Goniastrcea laxa, Quelch, Reef Corals, Challenger Reports, vol. xvi, part xlvi, p. 102, pi. 3, figs. 4- id. 



