DESCRIPTION OF CHALK CORALS. 281 
Believing, for the reasons already given, that a distinction from Jdmonea exists, 
the term Desmeopora (Séoun fasciculus) it is suggested might be adopted as a 
generic appellation for the zoophytes noticed in the preceding remarks. Re- 
specting the species of the English fossil, the resemblance is greatest with Jdm. 
(Desmeopora) semicylindrica of Herr Roemer—a prior determination to that of 
Dr. Mantell ; and as no marked differences have been detected, the name is re- 
tained provisionally, leaving to a careful comparison of specimens its final 
adoption or rejection. 
Desmeopora, n. g. 
Tubular ; branched ; tubes fasciculated, the free portion forming two rows of 
protuberances, apertures chiefly limited to the latter; surface of the branches 
foraminated wholly or in part ; internal composition, downward extensions of the 
fasciculi with a surrounding variable structure. 
Desmeopora semicylindrica. (Tab. XVIII. A. figs. 6 & 6 to 6.) 
Fixed at the base ; branches flat in front, rounded on the back ; free portion 
of the fasciculi protruded along the edges of the flat surface, conical in form, 
arranged alternately ; apertures of the tubes disposed in vertical rows, or inor- 
dinately on the back of the cones ; surface of the front including the projections 
traversed by slightly raised, variously inclined lamine or ribs, with intermediate 
rows of foramina; reverse side, laminz generally not raised, foramina very di- 
stinct ; branches chiefly thickened on the back, and for the greater part by an 
increase of the foraminated structure, but near the base by downward extended 
tubuli. 
Idmonea semicylindrica, Roemer? Versteinerungen des Norddeutschen Kreide- 
gebirges, p. 20. tab. 5. fig. 21,1840. Upper chalk of Riigen, upper chalk marl 
near Gehrden. 
The fine specimen delineated in ‘Tab. XVIII. A. was obligingly lent to Mr. 
Dixon by Mr. Bowerbank ; and figure 6, of the natural size, represents fully the 
general surface characters. The base or root was not sufficiently perfect for its 
nature to be ascertained, but the branches issued directly from the preserved 
portion, diverging and subdividing almost immediately ; and as they extended 
upwards, they were more or less contorted and reversed, also occasionally anasto- 
mosed. Respecting the mode of branching the principal subdivisions originated 
apparently in terminal partitions, each portion exhibiting an equal thickness, and 
a certain degree of symmetry with the other; but some of the truncated fasciculi 
