ps 
Pegs: 
a 
Fossil Corals of the family Cyathophyllide. 181 
is sometimes formed by a convolution of the septa or plates, as 
shown in some Columnarie. In the Sarcinule the septa extend 
quite from the sides, and appear like a series of funnels inverted 
upon one another, with a solid axis along the centyal line. 
Michelin first pointed out that certain species have on one 
side of the cell a narrow triangular depression or cavity, with 
one or more of the lamellz in part wanting, and designated the 
group Caninia. ‘This structure cannot be considered altogether 
anomalous, when we consider that some Madrepore and Zoan- 
thide have one tentacle different in size or color from the others ; 
and we need not look for an explanation of it to an analogy with 
the siphuncle of the Ammonite. 
We observe a farther Bitsterice between the coralla of the As- 
tree and the Cyathophyllide. In the former, when the cells are 
not contiguous, the limits of the stars are formed by a thickening 
and lateral coalescence of the radiating lamelle; and the inter- 
stices in a transverse section, constitute a narrow ‘bisa, often cel- 
lular, between the several stars; but in the latter, although there 
may be broad interstices petwee the cells, there are none be- 
tween the stars; they are separated only by a simple thread-like 
line. The lamelle, or their portions towards the circumference, 
often become subdivided, as in some recent Caryophyllide. It 
appears therefore that there is a decided difference in the struc- 
ture of the polyps. In Astras with contiguous cells, we have 
in a transverse section nearly the same structure as in the 
Cyathophyllide ; but, unlike the species of the group before 
us, they are dichastic in budding, the disks of the polyps gen- 
erally subdividing by growth. The interstitial buds of this fam- 
ily are in character like those of the Porites and Astroites, in 
which budding is lateral. The summit buds of the Cyathophyl- 
lidee differ decidedly from the disk-buds of the Astras. Their 
production is attended with a sacrifice of the parent, and they 
consequently grow up as prominent young, like the lateral buds 
of a Caryophyllia; while in the Astras, without the intermitted 
mode of growth and reproduction, and a prolate growth of the 
summits, the young and parent grow on together with an equal 
rate of increase. 
The Cyathophyllide afford examples of both aggregate and 
segregate Zoophytes. Some species form clumps of branches 
like those of many Muss and Euphyllie; while in others, the 
