70 



EOCENE AND LOWER OLIGOCENE CORAL FAUNAS. 



Septa thin, weak, with grauuhite sides. The principal septa vary from 20 

 to 24, between each pair of which there are three smaller septa. Between 

 each pair of septa there is often a row of small pits.^ Interseptal loculi not 

 filled with stereoplasm. The columella appears to be a basal deposit laid 

 down around the ends of the septa, and entirely independent of them. 

 The columellar substance is merely plastered on the septal margins and 

 has an independent origin. (See PI. IV, fig. 14.) The columellar space is 

 not solidly filled. 



Greater diameter of calice 

 Lesser diameter of calice . 

 Height of corallum 



Mm. 



19 

 16 

 15 



Mm. 



13 

 13.5 



13.5 



12 



13.5 



Localities. — Red Blufif, and near Shubuta, Mississippi. 

 Geologic occurrence. — Yicksbiu'gian stagc, Red Bluff beds. 

 Types. — From collection of T. 11. Aldrich in tlie United States National 

 Museum. 



Specimens. — Uuitcd Statcs Natioual Museum. 



Genus ALDRICHIA gen. nov. 



Corallum simple, small, elongate, compressed, attached by a very 

 short and small pedicel. Costre well developed, granulate. Calicular fossa 

 shallow. The columella in the lower part of the corallum consists of a few 

 trabeculse that reach across from some septa to those opposite; higher in the 

 corallum, lobes arising on the inner portion of the septa unite to the septa 

 and to one another. These pali-like lobes give to the upper surface of the 

 columella a papillate appearance. There are no true pali, and no essential 

 columella. Septa very slightly exsert, not very numerous, in type species 

 18 to 24. 



The septal composition, as made out, is as follows: 



At the wall a notch divides the inner portion of the septum from the 

 outside costal portion. This is similar to the condition seen in Platytrochus. 

 The septa are solid, with granulate sides. Looked at one way, the granules 



I These pits are probably for the insertion of the mescuterial muscles. 



