70 
ANNALS NEW YORK ACADEMY OF SCIENCES 
making the total number of secondary septa present in the adult corallite. 
Two more pairs of tertiary septa are added in the counter quadrants and 
three more in the cardinal quadrants. 
Figure 16 is a section from near the base of the calyx. All the primary 
and secondary septa project freely into the cup. The cardinal septum is 
hardly as large as the others. The alar septa and all the secondary septa 
are about equally developed and 
each has a tertiary septum abutting 
against it. The counter septum is 
developed to a more marked extent 
and is longer than the others and 
has a tertiary septum on either 
side. All of these sections were 
sketched from the end of the coral¬ 
lite as it was ground away and are 
therefore more or less diagram¬ 
matic. 
The statement stands unques¬ 
tioned that a type occurring late 
in geological time, at least a con¬ 
siderable time subsequent to the 
earliest occurrence of a type at all 
similar, is likely to be far from 
primitive in at least some respects. 1 
That the counter quadrants of 
a rugose coral are accelerated in de¬ 
velopment over the cardinal quad¬ 
rants is shown by the above dis¬ 
cussion of Stereolasma rectum. One 
tertiary septum has appeared in 
each counter quadrant before the 
appearance of even one secondary 
septum in the cardinal quadrants. 
Three secondary septa appear in 
each counter quadrant before the 
appearance of the first secondary septum in the cardinal quadrants. In all 
seven secondary septa appear in each of the counter quadrants, while only 
four arise in the cardinal quadrants. 
In Stereolasma rectum, moreover, the tertiary septa do not arise simul- 
Figs. 14—15. Stereolasma rectum. 
(Enlarged.) 
1 See C. E. Gordon, American Journal of Science, vol. XXI, pp. 109-127, Feb., 1906. 
