256 Mr. S. 0. Ridley on the Coral-fauna of Ceylon. 



species with several others under the name arabica ; but I 

 prefer, on the present occasion, to keep the original name, as 

 it applies to what seems to be a more or less distinct form. 

 It occurs also in the Red Sea (Milne-Edwards & Hairne). 



Cailoria ascensionis, Ridley, var. indica, nov. 



Platygyra ascensionis, Ridley, Ann. & Mag. Nat. Hist. (5) viii. p. 438. 



Calicles rapidly defined and seldom elongated ; extreme 

 diameter 2 to 4 millim. j a paliform, upwardly directed, thick- 

 ened and roughened process rises in many calicles from the 

 primary septum at the point at which it unites with the colu- 

 mella. This specimen is curiously variable as to the presence 

 or absence of the paliform process referred to ; a considerable 

 variation in the size of the calicles appears due to the presence 

 of perforating worm-tubes, causing condensation in parts. 

 The typical form of the species, from which this variety 

 differs in the points above noticed, was described from Ascen- 

 sion Island originally. Colony rising from a somewhat 

 spreading base to form a hemispherical head about 50 millim. 

 (2 inches) in diameter. 



Coeloria ceylonica } n. sp. 



Colony subhemispherical, massive. Calicles usually dis- 

 tinctly defined, occasionally forming short gyri, curved or 

 undulating, 10 to 11 millim. in maximum length; the fully 

 defined calicle polygonal, about 5 millim. in diameter \ depth 

 of calicles from summit of wall to surface of columella about 

 2'5 to 3*0 millim. Corallum dense and weighty. 



Two cycles of septa ; a rudimentary third not unfrequently 

 occurring as a ridge about # 5 millim. high and projecting 

 from the wall into the calicle, commencing near the free margin 

 of the wall ; primary and secondary* septa subequal, their 

 margins sloping down obliquely from summit of wall about 

 1 millim., and then falling perpendicularly down towards the 

 columella, the primaries reaching and uniting fully with the 

 latter, the secondaries stopping short of its upper part, but 

 uniting with it below. Septa thin ; the primaries and secon- 

 daries with few very fine granulations on their surface, and 

 with two or three blunt teeth on the lower part of their mar- 

 gin. Wall thin, barely *5 millim. thick at level of columella, 

 sharp above and serrate with the septo-costal ridges. Colu- 

 mella distinct, formed of few contort laminas connecting the 

 septa. 



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