632 



WM. H. EASTON 



Remarks. — Ontogenetically, this species is 

 characterized by the marked acceleration of 

 the counter quadrants and by the slow in- 

 sertion of metasepta after very early ma- 

 turity. 



Phylogenetic relationships are clearly with 

 the so-called "zaphrentid" types, and A. 

 geniculatus appears to be closely related to 

 A. adnatus. 



This species is readily identified externally 

 by the large, long, slender corallites which 

 may be geniculate and sparsely spinose and 



almost always show interseptal ridges and 

 septal grooves. 



REFERENCES 



Easton, W. H., 1945, Kinkaid corals from Illi- 

 nois: Jour. Paleontology, vol. 19, no. 4, pp. 

 383-389. 



Grove, B. H., 1934, Studies in Paleozoic corals: 

 Am. Midland Naturalist, vol. 15, no. 2, pp. 97- 

 137. 



Hill, D., 1935, British terminology for rugose 

 corals: Geol. Mag., vol. 72, no. 11, pp. 481-519. 



Manuscript received June 9, 1944. 



