68 
ANNALS NEW YORK ACADEMY OF SCIENCES 
article, an individual corallite held by the large calycular end was ground 
off at the tip very gradually on a plate of glass with fine emery, and each 
successive stage of development was carefully noted and sketched. These 
successive stages are enlarged and shown in the accompanying figures. 
These figures, with the exception of figures 3 and 7, are the successive stages 
in the development of a single individual. 1 
Figure 3 shows the tip of an individual with only the four primary septa 
present. These septa, however, are not disposed at right angles. The 
Figs. 3-11. Stereolasma rectum. (Enlarged.) 
alar septa are inclined toward the cardinal, thus leaving the counter quad¬ 
rant spaces considerably larger than the cardinal quadrant spaces. 
Figure 4 shows the slightly fractured tip, the first view of the individual 
which was followed throughout its stages of development. Here the four 
primary septa are present, and two secondary septa have appeared, one in 
either counter quadrant. These are distinctly not equal to the primary 
septa and are not radially placed, but are short and are joined by their inner 
border to the dorsal side of the alar septa. As they develop, this point of 
1 Figs. 3-16 are reproduced from a former article by the author on this species printed in the 
American Journal of Science for April, 1907. 
