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186 Fossil Corals of the family Cyathophyllide. 
a place in the science, Schweigger’s characteristics of it should be to 
some extent retained. 
Genus 6. Aracunopoytium, Dana. Aggregate Cyathophyl- 
lide, having the cells faintly radiate, (the rays often obsolete 
towards the margin;) texture of the corallum for the most part 
cellular; of the radiating lamelle, very minutely cellular. 
This genus includes the Acervularia baltica Fig. 1. 
of Lonsdale. ‘The faint rays and the general 
texture seem to show a relation to the Cystio- 
phylla. The rays under a microscope appear 
very delicately cellular, like the finest lace-work, 
instead of being solid plates, as is shown in the 
annexed cut, representing part of a section much 
enlarged: The stars, or separate polyps of a 
zoophyte, are usually without prescribed limits 
in the interior of the corallum. (Sil. System, pl. 
16, fig. 8 to 8e ; Schweig., Handb., p. 418.) 
_ The absence, on a polished transverse section, 
of circumscribed limits to the stars, which appears 
to be a general characteristic, shows some relation to the Fungide, and , 
the species may prove to belong to the tribe Astreeacea ; yet it is proba- 
ble that the polyps were prominent as in the Porites, and that the bud- 
ding was lateral or inferior, instead of superior. The texture below the 
centre of a cell is very imperfectly, if at all, transversely septate. 
. Cystiopnytium, Lonsdale. Quite simple or ramose 
Rihana Corallum not radiate, or rarely with distinct 
rays about the central area; texture of the sides, and usually of 
the whole corallum, spumioso-célltilir. 
The peculiar cellular structure of these species may at once be de- 
tected in the character of the lateral surface, especially after polishing 
off the exterior, if not before, when the cellules will be foynd to differ 
strikingly from the rectangular cellules of the Cyathophylla. 
he species are usually without rays to the cells; yet in some, faint 
lines may be perceived around the central area, and a transition may 
be thus traced to the Cyathophyllum structure. The absence of trans- 
verse septa along the middle of the corallum has been laid down as a 
characteristic of the genus, yet itis not universal; and we perceive 
here, also, progressive transitions towards the Cyathophylla. 
