802 



BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



on the dorsal, and in the larger vacuoles. We unfortunately have not yet dis- 

 covered the ovicell, so that we are not able to confirm the identity of this species 



with that of Lamouroux, as 

 noted by Jelly in 1889. 



Occurrence. Middle 

 Jacksonian: Wilmington, 

 North Carolina (rare) ; Bal- 

 dock, Barnwell County, 

 South Carolina (very rare) ; 

 Rich Hill, 5J miles south- 

 C D 



FIG. 259. Genus Siphodictynm Lonsdale, 1849. 

 A-D. Siphodictyum gracile Lonsdale, 1849. A. Frontal of 

 branch, X 8, from the Cretaceous of England. B. A thin 



east of Knoxville, Crawford 

 County, Georgia (very rare) . 

 Vicksburgian (Marianna 



Drancn. A s, ironi uie vjimaceuus ui nuigmuu. u. r*. mm -, . \ r\ -i 1 



slice from a branch, X 12, showing longitudinal and trans- limestone) : One mile north 



verse sections. C. Dorsal of a well preserved specimen, 

 D. Longitudinal section, enlarged. 



X 10. of Monroeville, 

 (very abundant). 



Alabama 



Geological distribution. Lower Oligocene (Latdorfian) of Germany. 

 Plesiotypes.Cat. Nos. 65332, 6547S, 65479, U.S.N.M. 



Genus CRASSOHORNERA Waters, 1887. 



1887. Crassohornera WATERS, Tertiary, Cyclostomatous 

 Bryozoa from New Zealand, Quarterly Journal 

 Geological Society, London, vol. 43, p. 349. 



Horneridae in which there are no frontal sulci. 

 Genotype . Crassohornera waipukurensis 

 Waters, 1887. 



e. Priabonian-Miocene. 



Genus SIPHODICTYUM Lonsdale, 1849. 



1849. Siphodictyum LONSDALE, Notes on fossil Zoo- 

 phytes, Quarterly Journal Geological Society, 

 London, vol. 5, p. 94. 



" Horneridae in which the epitheca on the re- mopo ' ra irreguhms Marsson, 1887, 

 verse side is thick. The apertures are in irregular, from the Cretaceous of the Island of 

 transverse series. The maculae (=vacuoles) oc- Riigen. (After Marsson, 1SS7.) 

 cur in single or double longitudinal series below the aperture. The reverse side is 

 ornamented by ridges (=nervi), which may be reticular." (After Gregory 1899.) 



Genotype. Siphodictyum gracile Lonsdale, 1849. Aptian. 



The ovicell is unknown, but the zoarial structure is certainly that of the 

 Horneridae. 



FIG. 260. Genus PJiormopora Mars- 

 son, 1887. 



Frontal and dorsal and end 

 views, X 16, of a branch of Phor- 



