A. FE. Verrili—A ffinities of Paleozoic Tabulate Corals, ete. 187 
& 
Art. XXIII.—Brief Contributions to Zovlogy from the Museum 
of Yale College. No. XVIUL—On the Affinities of Paleozoic 
Tabulate Corals with Existing Species; by A. E. VERRILL. 
i by the lower parts of the bodies of the coral-polyps, thus 
lviding the lower, unoccupied portion of these coral-cells into 
former position of the base of the polyp, which occupied the 
cell, as it grew upward. In most of the other corals, on the 
contrary, there are either no transverse plates, or else they exist 
between the radiating lamelle or septa, thus dividing each of 
the radiating chambers into a series of transverse cavities, which 
formed after each discharge of ova; the vacuity thus produced, 
chambers, the septa formed below them in the different cham- 
bers will not be coincident, or exactly at the same level in all. 
We should, naturally, expect to find such variations in peri- 
odicity among the species and genera of many diverse groups, 
