222 
SILUEIA. 
[Chap. X. 
under the common name of ' Cyathophylla,' should be regarded as true Polyps. 
MM. Edwards and Haime, in framing those great subdivisions of their ' Coralliaria,' 
remarked their striking dissimilarity to the other Actinozoa. Professor Agassiz, in his 
grand Monograph on the Acalephse of North America, considers these differences so 
important that henceforth all connexion between the above-named groups and the Zoan- 
tharia aporosa and Z. perforata will be impossible. But besides these peculiar charac- 
teristics of the Z. rugosa .... several are provided with an operculum of very strange 
shape. .... Several of these operculated fossils have been placed with the Brachio- 
poda and other classes." M. Lindstrom carefully describes and figures Goniophyllum 
pyramidale (Turbinolia, Hisinger), Bhizophyllum Grotlandicum (Calceola, F. Boemer), 
Calceola sandalina, Hallia calceoloides, &c, and he brings together information relating 
to the operculum and other features of Cyathophyllum, Hypodema, Cystiphyllum (?), 
Cyathaxonia (?), &c, and offers the following conclusions: — 1. That the Bugosa must 
be separated from the Actinozoa, or the true Corals ; 2. That they form a class of their 
own in the great division of Badiata ; 3. That Goniophyllum pyramidale is an un- 
doubted Bugosum, in its shell and in its operculum, and that it coincides with the 
three species of the old genus Calceola, and that these are no longer to be numbered 
amongst the Brachiopoda, but are Bugosa. M. Lindstrom is inclined to agree with 
Agassiz that the Bugosa had close relation with the existing Lucernarise. 
Of Cystidea the forms are rare, but remarkable and characteristic, the species 
in the Upper Silurian being all furnished with what Edward Forbes called ' pec- 
tinated rhombs.' The fine species shown in Foss. 55. f. 1, has three of these 
curious markings, the usual number possessed by British Upper Silurian forms j 
while they are often much more numerous in those few Lower Silurian genera 
which possess them at all. The nature of these rhombs is not yet fully under- 
stood. The following species of Cystidea have been collected at Dudley by 
Mr. Gray and Mr. Fletcher* of that neighbourhood : — Pseudocrmites magnificus, 
f. 1 j P. quadrifasciatus, f . 2 j P. bifasciatus, and P. oblongus, Forbes f ; Apio- 
cystites pentremitoides, f. 4 ; Prunocystites Fletcheri, f. 3 ; Echino-encrinites 
baccatus, f. 5, and E. armatus, f. 6. Under the upper right-hand figure, one of 
the curious 5- or 6-valved ovarian openings is shown, and the two halves of a pec- 
tinated rhomb, occurring, as usual, opposite each other on neighbouring plates. 
The genus Echino-encrinites, but with different species, is found in the Lower 
Silurian rocks of Kussia. In North America, the representative of the Wenlock 
Limestone (the 1 Niagara group ' of New York) contains some characteristic 
Cystidea of similar forms. 
Passing on to the great group of Crinoid animals, which are numerous but 
rarely perfect in our Lower Silurian division, we find the Upper very rich in 
forms of this class. Many of these are yet undescribed, and we can only, at 
present, refer to those figured in our Plates XIII.-XV., and to a few other species 
that have been published in the works of Austin, d'Orbigny %, &c. 
* Mr. Gray's Collection is now in the British T Austin, Monograph of the Crinoidea, 184-1 ; 
Museum, and Mr. Fletcher's in the Woodwardian d'Orbigny, Prodr. de Pale'ontol. Universelle, 1849, 
Museum. p. 45 & c . 
t Memoirs Geol. Surv. vol. ii. pt. 2. pp. 496 et seq. 
Fossils (55). Cystidea of the Wenlock Limestone. 
1. Pseudocrinites magnificus, Forbes. 
2. P. quadrifasciatus, Pearce. 3. Pru- 
nocystites Fletcheri, Forbes. 4. Apio- 
cystites pentremitoides, Forbes. 5. 
Echino-encrinites baccatus, Forbes. 6. 
E. armatus, Forbes; with its ovarian 
pyramid and a rhomb. 
