684 



BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



certain of the determination the originals should be examined, but this has not been 

 possible. 



This species differs from Heteropora ovalis in its orbicular orifices and in its 

 zoarial apophyses. 



Occurrence. Claibornian (Gosport sand) : One mile southwest of Rockville, 

 Clarke County, Alabama (rare). 



Lower Jacksonian (Moodys marl) : Jackson, Mississippi (very rare). 



Plesiotype.C&i. No. 65433, U.S.N.M. 



H *> 

 FIG. 223. Forma Multicrescis D'Orbigny, 1852. 



A-G. Multicrescis variabili-s D'Orbigny, 1852. A. Different forms of the zoarium, natural 

 size. B. A zoarium, X 4, showing the superposed layers of tubes. C. Portion of the surface 

 much enlarged. (A-C after Novak, 1877.) D. A claviform zoarium, X 5. B, F. Two aspects of 

 the surface enlarged, showing the zooecia varying in size according to that of the mesopores. G. 

 Portion of transverse section through a zoarimn. (D-G after D'Orbigny, 1852.) 



H. Multicrescis tuberosa Romer, 1839. Part of vertical section, X 7, showing the beginning 

 of an upper layer. (After Gregory, 1909.) 



Genus MULTICRESCIS D'Orbigny, 1852. 



1852. Multicrescis D'ORBIGNY, Palfiontologie frangaise, Description des animaux invertSbres, 

 Terrain O&tac6, vol. 5, p. 1073. 



The zoarium is massive or branched and composed of successive thin layers of 

 zooecia. 



Genotype. Multicrescis varidbilis D'Orbigny, 1852. 

 Range. Neocomian-Helvetian. 



