Palconloloffy of the Ciiidmiati (,'roup. I47 



Remarks. — This genus is closely allied to Strcptclasma, differ- 

 ing from it only in forming masses instead of being single 



and simple. 



1. — P. DIVAKICAXS, Nicholson, 1S75. 



Corallum usually free, sometimes apparently attached, com- 

 pound, formed of from 2 to 6, conical, turbinate corallites, 

 produced by lateral .y^emmation, or by fission, directed 

 outward from the parent at a more or less open angle 

 and not again in contact; septa from 58 to 62, alternately 

 large and small, large ones twisted toward center of visceral 

 chamber; no dissepiments or columella; tabuke unknown; 

 epitheca well developed, with ridges corresponding to the 

 septa within, with faint encircling stride and a few shallow 

 annulations of growth ; calice deep, with a flattened space at 

 bottom ; free edges of septa without spines or denticulations. 

 (Pal. of Ohio, vol. 2, 1875, p. 220.) 



Locality. — Oxford, etc., O. 



Section 3. — Madnporaria perforata. 



Simple or composite, with the corallum more or less porous 

 or reticulate : septa solid or porous, represented by irregular 

 trabecule [plates or bar.s] or calcareous spines ; dissepiments 

 usually present, and tabuke commonly developed. (Nicholson, 

 Man. of Pal., r88g, vol. i, p. 306.) 



This section includes many of the large, widely distributed 

 and best known genera of Paleozoic corals, among them being 

 Favosites. Only three genera are represented in our section, 

 and these with only a few species. They are Alveolites, Pro- 

 tar cca, and Calapd'cia {Colnnniopora). 



Genus i. — Alveolites, L,amarck, iSoi. 



Corallum massive, incrusting or ramose, composed of con- 

 tiguous, compressed corallites, which possess thin walls and 

 open obliquely upon the surface by sub-triangular or .semi- 

 lunar calices ; .septa .sometimes obsolete, but often present in 

 the form of longitudinal rows of spinules, which may be 

 equally developed or reduced to a single, double or treble row 

 by the suppression of the others ; tabulse well developed, com- 



