28 
terms of a HelioUtes, speaking of autopores, siphonopores, and pseudosepta. 
The identification was made from Rominger’s figures and hence need not 
necessarily be correct. If he were looking at a Calapoecia then the occasional 
boundaries of wdiat he regarded as siphonopores were “ costae ” cut across 
in longitudinal section. His figure 14 could be construed in this way. 
With regard to his figure 13, it is possible that he saw “ costse ” radiating 
from a corallite and has drawn them as confluent with those of its neigh- 
bours, by inference. The spaces between “ costse ” (if it is a Calapoecia) 
he calls siphonopores. But Sardeson was evidently not certain about his 
identification. From his rather unsatisfactory description it seems probable 
that Sardeson is considering a specimen of C. canadensis var. anticostien- 
sis. His notice of the irregularity of coenenchymal structure at the contact 
with corallites also recalls the behaviour of this variety. Sardeson gives 
the number of septa as up to 25, which, if it is a true count, would place his 
specimen elsewhere. But as the septa are difficult to count except in thin 
section it is possible that there is inaccuracy. In view of the analysis above 
the writer is inclined to believe that Sardeson was describing a Calapoecia. 
Lindstrom classed Calapoecia with the Heliolitidae in 1876 (12 and 17), 
but later (1899, 25) revised this view “ as it is provided with a perforated 
theca, with an unstable number of septa, twenty or more or less, and a 
quite different sort of coenenchyma.” He gives England as a locality and 
thus was presumably including Lyopora. This w'ould account for his opin- 
ion that tho septa varied in number. The difference between the coenen- 
chyme of Calapoecia and the Heliolitidae has already been discussed. 
The most convenient course with regard to its systematic position 
is to consider Calapoecia as a member of the Tabulata. It is aberrant in 
that there is no true wall and in the thickening (not stereoplasmic) of the 
septal elements. Professor Smyth has drawn my attention to a certain 
Chaetates which has thickened its walls phenomenally (Smyth, 1925). The 
constant number of septa and their spinose nature favours the inclusion 
of the genus Calapoecia in the Tabulata. 
