
462 THE AMERICAN NATURALIST [VoL. XXXVI. 
Sections of another colony, composed of four individuals, 
showed that the four corallites remained at approximately the 
same proportional size throughout, and the writer assumes that 
the mass was formed by four larvz which settled close to one 
another and practically at the same time, each constructing its 
own corallum, and contributing an equal share to the formation 
of the common investing skeleton. 
The late Prof. H. de Lacaze-Duthiers! has recently given an 
account of somewhat similar aggregations of the simple coral 
Caryophyllia, obtained from Port-Vendres. On many of the 
larger corallites smaller examples were growing, in such a way 
as to leave little doubt that the * bouquet" was a result of the 
adherence of Caryophyllia larvae to the corallum of a polyp 
already established. Occasionally the individual members of a 
colony are polyps of practically equal size, as if originating 
from larvz which settled simultaneously and in close proximity. 
In most of the examples described and figured by Lacaze- 
Duthiers the corallites retain their individuality, without the 
formation of a common secondary skeletal mass, but in one 
specimen (/oc. cit., Pl. XV, Fig. 12) two calices appear to have 
fused at their margin. 
Prof. C. Schuchert has drawn my attention to the colonial 
condition generally exhibited by the rugose coral, Strepte- 
lasma (Paleophyllum) divaricans (Nicholson)? Representatives 
of the genus Streptelasma are usually simple, but numerous 
specimens of the above species in the collections of the United 
States National Museum, collected from near the top of the 
Lower Silurian of Ohio, constitute small colonies of two to six 
individuals. The colonies were at first supposed to have been 
formed “by lateral gemmation, or rarely by fission,” but a 
close examination shows that such an explanation is very 
improbable. Each member retains more independence of form 
than is usual in colonies produced by gemmation or fission. 
In many instances two or more corallites are found adhering to 
some foreign object, such as a shell of Rhynchotrema capax or 
x Lacaze-Duthiers, H. de. Les Caryophyllies de Port-Vendres, Arch. de Zoól. 
Exp. et Gen., Ser. 3, vol. vii, ¥: 
.* Geol. Surv. Ohio, Pal. 11, c p. 220, Pl. XXII, Figs. 10, 10 4. 
