424 PROCEEDINGS : BOSTON SOCIETY NATURAL HISTORY. 
Phylogeny. In Cercitopora distorta we have a form intermediate 
in structure between C. dichotoma and C. jacksoni , and a species 
therefore which more nearly conformed to the characters of the 
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radical of the three species than either of the other two. In the 
young of C. distorta , we may with a reasonable degree of accuracy, 
suppose to have typified the young of each of the three species, as 
well as the characters of the proximal radical. As already remarked, 
the young of G. distorta closely resembles the initial tube of an 
Aulopora. It is true, that the absence of trabeculae in the young of 
C. distorta is not absolutely proved, the two specimens which have 
come under observation being insufficient to establish this point. 
The thickening of the walls and the formation of cysts are clearly 
secondary features, not occurring in the young, so that, even if the 
trabeculae are present, the relation between the two genera is not a 
very distant one. The similarity in all the determinable points of 
structure extends even to the manner of budding, which is aulopo- 
roid, and to the habit of fixation in early life. If we are warranted, 
as it seems we are, in regarding this similarity of form and structure 
as indicative of relationship, we are furnished with a clue to the 
probable origin of the family Moniloporidae. It seems very probable 
that Nicholson’s suggestion, that Monilopora represents a branch of 
the Auloporidae, is correct, and true of the family, the immediate 
connection being through the more primitive species of Ceratopora. 
Monilopora is probably not a direct descendant of any of the 
known species of Ceratopora, though following them in the geologic 
record. It is probable, that when the numerous corals of the 
western Devonian coral reefs are studied in detail, intermediate 
species will be discovered, which will establish the genealogy of 
Monilopora more precisely. 
I take pleasure in acknowledging my indebtedness to Prof. 
Charles E. Beecher, of Yale university, who generously placed many 
of the fossils herein described unreservedly at my disposal. 
Printed , April , 1899. 
