84 MADREPORARIA. 



The specimen in the Cambridge Museum is a fair-sized stock (broken into three 

 fragments, which fit together). The specimen in the British Museum shows all the important 

 characters. 



One is at once struck by the general similarity between the shallow calicles with the 

 low thick wall, like a network on the surface, of all these columnar and branching forms from 

 Singapore. But similar as they are to the naked eye, the differences when closely examined 

 (cf. the magnified figures of the calicles, PI. VI. figs. 1-2 with 3 and 4, and these again with 

 7-8, and with fig. 9, PI. V.), coupled with the differences in growth-form (cf. PI. XII. 

 figs. 12, 13, and PI. XIII. figs. 1 and 3), are too great for them to be included under one and 

 the same heading. See the observations on the Singapore forms. 



a. Presented by the Cambridge Museum. Zool. Dept. 1902. 9. 9. 8. 



There is another specimen in the University Museum at Cambridge. 



54. Ooniopora Singapore . (PI. XIII. fig. 4.) 



[ ? Exact locality, coll. Bedford and Lanchester ; Cambridge University Museum.] 



This coral has been already briefly described (see 7 p. 76). It shows almost the same 

 method of growth as G. Java Sea 1, which see for description and illustrations. Cf. also the 

 observations on the variations in structure shown by the Singapore specimens below. The 

 coral is not perfectly hemispherical, but slightly compressed laterally, and with swollen top. 



Observations on the Singapore Forms. 



The series from this locality provide remarkable evidence for the interdependence of 

 growth-form and the type of calicle. 



The series of Diagrams on p. 24 (Introduction) will serve to explain the conditions. 

 The hemispherical stock G. Singapore 6 has deep calicles everywhere except round the base. 

 In the pear-shaped stocks the zone of shallow calicles with central rosettes extends still 

 further, until in the columnar G. Singapore 2 and in the finely branching G. Singapore 1 

 the deep calicles are confined entirely to the growing points. The deep calicles never have 

 central rosettes of pali, which are typical of shallow lateral calicles. 



We have, unfortunately, no data for correlating any other characters of the calicles 

 which bear a superficial resemblance to one another through all the series with their special 

 growth-forms. We may, however, note that the light, open, reticular calicles (PI. VI. figs. 1 

 and 2) belong to the form which, from the size of the columns and the extent of the living 

 layer, seems to have grown very rapidly, while the calicles (PL VI. figs. 7 and 8), which are 

 composed of solid granules, belong to a totally different form in which upward growth seems 

 to have been slow. 



These facts are sufficient to show that the representatives of the genus in any locality 

 may show series of transitions, each characterised by a group of obviously interdependent 

 variations. If this is so, it is enough to shake our belief in the stability of any single 

 character other than those which mark the genus. Until we have more evidence, it is possible 



