DESCRIPTIONS OF SPECIES. 



185 



Greater diameter of calice 



Lesser diameter of calice 



Height of ooralluiii 



Length of pedicel 



Lesser diameter of pedicel, al)0ut . . 

 Greater diameter of pedicel, about . 



Mm. 

 6 



4.5 

 6 

 2 



2.5 

 3 



Min. 



5.7 



4.2 



6.5 



2 



Localities. — Claibome, Alabama (L. C. Johnson, collector) ; and Jackson, 

 Alabama (C. W. Jolmson, collector). 



Geologic occurrence. — Claiboriiian stage (horizon of Claiborne sands). 



Types. — United States National Museum. 



In the material from Claiborne in the National Museum, are several 

 excellent young specimens. The following notes are based on them: 



PI. XXI, fig. 12, represents the youngest. It is attached to a specimen 

 of Dentalium blandum de Grregorio. The basal plate is well preserved; it 

 forms a thin coating on the shell, and around its outer edge bends upward. 

 The original number of septa is twelve. Their inner ends do not meet in 

 the center; the latter is an open space with a few papillae resting on the 

 basal plate. Their outer ends do not reach the upturned peripheral edge of 

 the basal plate. 



The next stage is represented by PI. XXI, fig. 13. This is a view of 

 the l:)asal end of a specimen. The twelve primary septa are shown. In 

 the figure their inner ends seem fused, but in reality a portion of the 

 basal plate still adheres to the septa; by turning the specimen one can see 

 beneath its sharp edge. The septa have been extended peripherally to the 

 upturned edge of the basal plate; the soft parts of the coral have over- 

 flowed it, and have built a porous wall outside of it. This specimen is 

 about 2 mm. high; the greater diameter of the calice is about 3.2.5 mm., 

 and the lesser, 2.5 mm. An examination of the calice shows three complete 

 cycles of septa (reckoning six septa in the first cycle). The members of 

 the third cycle are longer than those of the second, and grow to meet the 

 columella beyond the latter, or may fuse in front of them. One of the 

 second cycle may sometimes fuse to the side of one of the third. The 

 columella in this stage is well developed and possesses a soft, spongy 

 texture. 



