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- 
east of Knoxville, Crawford 
Fig. 259. — Genus Siphodictyum, Lonsdale, 1849. r . , 
County, Georgia (very rare). 
A-D. Siphodictyum gracile Lonsdale, 1849. A. Frontal of A7 . , , . /nvT . 
branch, X 8, from the Cretaceous of England. B. A thin . Vicksburgian (Marianna 
slice from a branch, X 12, showing longitudinal and trans- limestone) : One mile north 
verse sections. C. Dorsal of a well preserved specimen, X 10. of Monroeville, Alabama 
r>. Longitudinal section, enlarged. (very abundant). 
Geological distribution. — Lower Oligocene (Latdorfian) of Germany. 
Plesiotypes. — Cat. Nos. 65332, 65478, 65479, TJ.S.N.M. 
Genus CRASSOHORNERA Waters, 1887. 
1S87. 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. 
Range. — Priabonian-Miocene. 
Genus SIPHODICTYUM Lonsdale, 1849. 
Fig. 260. — Genus Phorrnopora Mars- 
son, 1887. 
Frontal and dorsal and end 
views, X 16, of a branch of Phor- 
mopora irregularis Marsson, 1887, 
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 
verse side is thick. Jhe apertures are in irregular, from the Cretaceous of the Island of 
transverse series. The maculae (= vacuoles) oc- Riigen. (After Marsson, 1887.) 
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. 
