306 



ones, occupy the interspaces, but extend only a short distance into the 

 cup. Margin of the cup extended on the dorsal side. 



This species is rather abundant, and may be easily recognized by 

 the tlattened outer surface, which is often so great as to give a 

 transverse diameter double that in the opposite direction. Specimens 

 are met with measuring from a fourth of an inch to more than an inch 

 in length. 



Genus Zapiirentis, Rafinesque. 

 Zaphkentis acutus (n. sp.) 



Coral small, or of a medium size ; subturbinate, gently curved, 

 acutely pointed at the base, more rapidly expanding and somewhat 

 inflated near the middle. Margin of the cup oblique to the axis, 

 transverse section circular. Cavity of the cup of moderate depth, 

 with from twenty-five to thirty-five thin longitudinal rays, which unite 

 in the border of a deep subcentral fossctte. Fossette large, extending 

 from the centre to the margin on the short side ; elongate ovate or 

 clavate in form, widest at the inner end ; outer end occupied by a 

 single ray. Transverse septa extending from the border of the central 

 fossette to near the external walls, leaving small perforations into the 

 lower .chambers. Outer walls and longitudinal septa thin and smooth ; 

 exterior surface smooth (perhaps from weathering). 



Genus Favosites, Lam. 

 Fa vo SITES. 



Coral irregularly hemispherical ; cells strong, very rapidly diverging 

 from the base, increasing by frequent interstitial additions ; vertical 

 walls proportionally thick, and apparently smooth on the surfaces. 

 The pores of the cqII walls have not been observed, owing to the 

 strongly crystalline nature of the material filling them. Transverse 

 partitions thin, closely arranged ; from two to three in a space equal 

 to the transverse diameter of the cell ; less numerous near the com- 

 mencement of the individual cells. 



This species differs from similar forms in the lower rocks, and 

 especially from most species in rock of a similar age, in the great 

 divergency of the cells and in their more rapid increase in number. 



