LOStae BRITISH PALZZOZOIC FOSSILS. [Zoopnyra. 
quently named Lobophyllia by Blainville; which latter name, therefore, becomes a synonym merely of 
Lithodendron: the two latter of these examples belong to the genus Lobophyllia, as restricted by MM. 
Edwards and Haime, but they have formed the type of the two first into their new genus Lusmilia, 
which latter therefore should, according to the usual rules, be considered the true Lithodendra, and bear 
that name if it be used at all. In no case can the Siphonodendra of the mountain limestone be brought 
in any close relation with those recent and mesozoic types. The differences are briefly these: first, 
Siphonodendron increases by lateral buds,—Lithodendron by a lateral elongation and gradual division of 
the old cup and dichotomous fissure of the stem; second, Siphonodendron has a slender, distinct, simple 
axis, and wide conoidal transverse diaphragms, while Lithodendron has a large cellular axis, and no 
diaphragms. 
SIPHONODENDRON AGGREGATUM (J/°Coy). 
Ref. and Syn —Lithodendron pauciradialis M°Coy, Carb. Foss. Irel. t. 27. f. 7. 
Sp. Ch.—Corallum of numerous, slightly flexuous, nearly parallel tubes, two lines or slightly more in 
diameter, either round and smooth or marked with very fine transverse striz of growth, or very often 
prismatic, from mutual pressure, and then marked with vertical lamellar strize five in one line; columns 
often coalescing laterally; branches few; radiating lamellse about twenty-two, reaching to the central, 
conical projection of the diaphragms, or to the central styliform axis, according to the height of the 
section, between each pair in some tubes are an equal number of short secondary ones, two of the 
lamellee stronger than the rest seem to pass through the centre, and the two lateral next ones often unite 
branch-wise to it; external vesicular perithecal area very narrow, about two cells wide: vertical section 
shews at the sides, the outer epithecal wall, the very narrow perithecal area of one or two cells wide, 
and transverse diaphragms (three in one line) converging upwards to the persistent filiform axis. 
This species is remarkable for its peculiar mode of branching, or crowded, nearly parallel mode of 
growth. I alter my first name, as I now believe that all the primary lamellz are of nearly equal length, 
so that the number is not particularly small, and I propose one alluding to the peculiar mode of growth. 
Position and Locality.—Common in the carboniferous limestone of Corwen. The original Irish locality 
was the Arenaceous limestone of Magheramore,. Tobercurry. 
SIPHONODENDRON FASCICULATUM (fem. Sp.) 
Ref. and Syn.—Lithodendron fasciculatum Phil. Geol. York. Vol. I. t. 2. f. 16 and 17. 
Sp. Ch.—Corallum forming very large masses of loosely aggregated, slightly flexuous tubes, averaging 
three lines in diameter, branching and occasionally coalescing laterally ; external or epithecal wall strong, 
marked with distant, obtuse ridges, about five in two lines, but when slightly worn the vertical costal 
edges of the lamellze are seen five in one line: vertical section shews within the outer wall, a very 
narrow vesicular perithecal area, separated by a thin wall from the inner area, or true cell-tube, which 
latter is traversed by wide, conoidal diaphragms, converging upward into an axis, about two diaphragmatal 
spaces in one line: horizontal section shews the circular boundary wall of the cell-tube, surrounded by 
a very narrow perithecal vesicular area, enclosed by the epithecal or external wall, and radiated by costal 
extensions of about forty-four radiating lamellz, one half of which extend to the axis, the remaining 
twenty-two barely entering within the lamelliferous tube; axis very variable, usually presenting, a slightly 
radiated vesicular crumpling of the conical centres of the diaphragms, sometimes appearing as a smaller 
solid point; terminal cups very deep, lined by the radiating lamella, and having the slender, styliform 
axis, very prominent in the bottom. 
Position and Locality.—Abundant in the carboniferous limestone of Derbyshire ; carboniferous limestone, 
Bristol. 
