q8 
is reported from Ternate, Borneo, Zanzibar, and Madagascar; D. jlorida from Hong Kong, the 
Philippines, and Port Jackson (Australia). 
It may also be pointed out that certain factors in the immediate environment in different 
parts of a large colony must show considerable diversity, e.g. as regards shelter; and yet, as 
already pointed out, there is rarely diversity within a colony except in colour and the like. 
(c) It may be, however, that the observed differences are expressions of individual intrinsic 
variability, not correlated with any peculiarities of environment. There is no way of testing this 
interpretation until numerous similar specimens from the same locality and of the same age and 
size are examined by some investigator with abundance of living material at his disposal. 
II. It may be that the multiplicity of distinct forms within a narrow range is due to 
cross-fertilization between allied species. It is quite conceivable that species which have attained 
individuality and fixity in the course of isolation and inbreeding may be brought into contiguity 
by subsequent spreading or removal of barriers. In such a case, analogy points to the likelihood 
of numerous new patterns arising by permutations and combinations of the previously segregated 
characters. This hypothesis is certainly suggested by the fact that two species may agree in 
anthocodial armature and yet differ in mode of branching, or may agree in having a foliaceous 
collar and yet differ in the nature of the 'supporting bundle. In short, in the distinctions between 
species there is a distinct suggestion of the shuffling of unit characters. 
III. There seems to be a third possible interpretation — namely, a mutation of species 
apart from any hybridizing influence. It may be that certain widespread and strongly established 
species such as D. gigantea , D. ehrenbergi , and D. brevirama have been the stocks from which 
mutations have been thrown off after the fashion of Odnothera lamarckiana. 
An indirect argument in favour of this interpretation may perhaps be found in the possi¬ 
bility of discriminating similar radiations of evolution within the three great groups: Glomerates, 
Divaricates and Umbellates. A more direct argument may be found in the variability of certain 
species such as D. gigantea , to which reference has already been made. As Kukenthal remarks, 
„Aus diesen Beschreibungen geht hervor, dass D. gigantea eine in ihrem Aufbau sehr variabele 
Art ist”. (“Revision”, p. 553). 
Divisions of the genus. 
Kukenthal arranged the species of Dendronephthya in three main divisions: (I) Glomeratae; 
(II) Divaricatae; (III) Umbellatae, giving precision to similar suggestions by previous workers, 
such as Holm. 
I. The Glomeratae are characterized by: 
(a) the comparatively slight branching of the polyparium; 
( b ) the grouping of numerous bundles of polyps into roundish bunches which very markedly 
break up the surface of the polyparium. 
There is a marked definiteness about the Glomerate division which suggests “naturalness” 
OO 
and makes it easy to refer a species to the group. Plate XVII, Fig. 1 is a diagrammatic 
representation of what is meant by the Glomerate habit of growth. 
