the Collection of the British Museum. 419 



ramose. Branches subangular, of moderate thickness, much 

 divaricate, but scarcely coalescing, ramified at nearly right 

 angles ; branchlets more or less horizontal, straight, slender, 

 needle-pointed. Calicles small, in rather irregular rows, those 

 of the same row distant by nearly the length of their diameter ; 

 the interspaces on the average double as broad as the rows. 

 Cells slightly vaulted and labiate ; their edges strongly promi- 

 nent, fimbriate. Septa of first cycle moderately well developed. 

 Columella low, thick, somewhat pointed. Surface of cosnen- 

 cliyma rather smooth, granulate. Diameter of principal 

 branches about 5 millims., of branchlets at their base 2 millims., 

 of calicles two thirds of a millim. 



Hah. Feejee Islands [F. M. Rayner in B.M.). 



This species is remarkable by being much more arborescent 

 than its allies, a character arising from the fact that the 

 ramification is not evenly dichotomous, but generally only 

 one of the branchlets attains a larger size and continues to 

 divide. From 8. hystrix it differs in its mode of growth and 

 in the thinner and more angular branches. In the broad and 

 flat interspaces between the rows of calicles, and in its mode 

 of ramification, it shows some resemblance to 8. spinosa. 



5. Seriatopora caliendrum. B.M. 



Seriatopora caliendrum, Ehrenberg ; Dana ; M.-Edwards. 



This species forms large clumps of subparallel and more or 

 less perpendicular branches, these being thin and slender, but 

 rather obtuse at their summits. 



Hah. Red Sea [Ehrenberg) ^ Tur near Sinai {HdckeV) ; 

 Madagascar (B.M.). A variety is recorded by Dana from the 

 Sooloo Sea, under the denomination 8. caliendrum^ var. 

 gracilis ; and there is a specimen in the Museum collection 

 marked " Navigators' Islands," which I am not able to sepa- 

 rate as a distinct species. 



There appear to exist intermediate forms between this and 

 the preceding, and again between the latter and 8. hystrix, 

 which in its turn comes very near to 8. cervina. However, 

 the material in the Museum is not extensive enough to ascer- 

 tain the nature of these transitions, especially with regard to 

 the question how far they coincide with the geographical dis- 

 tribution, or whether they represent merely individual pecu- 

 liarities. 



6. Seriatopora octoptera. B.M. 



Seriatopora octoptera, Elirenberg ; Dana ; M.-Edwards. 

 A very distinct species, whose characters have been well 



