AND AFFINITIES OF GUYNIA ANNULATA. 
33 
The following is the diagnosis of the Cyathaxonidce , the second family of the section 
Rugosa* : — 
“ Corallum having a well-developed septal apparatus, the laminse extending uninter- 
ruptedly from the base to the summit of the visceral chamber, and leaving open fossulse 
between them without dissepiments, tabulae, or synapticulse. The primary septa are not 
decidedly more developed than the others, and do not form a cross as in most of the 
Stauridae.” 
Up to the present time but one genus has been associated with this family, viz. Cya- 
thaxonia, Michelinf ; it is thus described by MM. Milne-Edwards and Jules HaimeJ: — 
“ The corallum is simple, free, finely pedicellate, and has the shape of an elongate 
and curved cone. There is a complete epitheca. There is a well-developed septal 
fossula situated on the side of the great curvature. The columella is styliform and 
very projecting. The septa are smooth and numerous, and most of them unite with 
the columella.” 
The accretion-ridges and wall are particularly well marked in Cyathaxonia tortuosa, 
Michelin, and the size of the septal fossula varies with the species. The genus was 
represented in the Upper-Silurian strata of Gothland, and perhaps in the Ludlow rocks 
of England, but its species have not been found in Devonian strata : nevertheless it is 
not a rare fossil genus in the American and Belgian Carboniferous strata. Cyathaxonia 
cornu , Michelin, is said to be found in English and Belgian Carboniferous deposits. 
The great distinction between Guynia and Cyathaxonia is the absence of the septal 
fossula in the first genus ; but its species has a large septum, which is a very marked 
rugose peculiarity, and the replacement of such septa by depressions or fossulse is common. 
There is therefore no reason why Guynia annulata should not be placed in the family 
of the Cyathaxonidce, and that its genus should not be closely associated with Cyathaxonia §. 
IV. Count Pourtales describes the genus Haplophyllia (Plate I. figs. 13-15) as 
follows || : — 
“ Corallum simple, fixed by a broad base, covered with a thick epitheca ; columella 
styliform, strong, very thick at the base. Interseptal chambers deep, uninterrupted by 
tabulae or dissepiments, but filling up solid at the bottom.” 
An introductory paragraph supplies the defective information respecting the septal 
apparatus, tie therein states : — “ The singular coral next to be described strikes one at 
first sight by its resemblance to some of the members of the group of the Rugosa of 
Milne-Edwards and Hatme. A closer examination tends to confirm that view, much as 
it seems improbable to find a living representative of a group so long extinct. In no 
other division of the corals is the septal apparatus subdivided into systems that are mul- 
tiples of four ; but such is the case in our specimen, though a little obscured by acci- 
* Hist. Nat. des Corail. vol. iii. p. 329. t Icon. Zooph. 1846. 
X Op. cit. p. 329. § I have named the genus after Mr. Gwyn Jeffreys, F.E.S. 
|| Op. cit. p. 140. «[[ Pages 139 and 140. 
F 
MDCCCLXXII. 
