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THE VOYAGE OF H.M.S. CHALLENGER. 
§ /3. spinosce. 
(3) Membranipora spinosa, d’Orbigny. 
(4) Membranipora galeata, Busk. 
2. Amphiblestrum, Gray. 
(1) Amphiblestrum imbricatum, n. sp. (PL XV. fig. 3). 
(2) Amphiblestrum cristatum, n. sp. (PL. XV. fig. 1). 
(3) Amphiblestrum papillatum, n. sp. (Pl. XXXIII. fig. 1). 
(4) Amphiblestrum cervicorne, Busk. 
(5) Amphiblestrum umbonatum, Busk. 
(6) Amphiblestrum capense, n. sp. (Pl. XXIII. fig. 3). 
3. Bijlustra, d’Orbigny. 
Bijlustra savartii (Audouin) (Pl. XIV. fig. 2). 
4. Foveolaria, n. gen. 
(1) Foveolaria elliptica, n. sp. (Pl. XXIII. fig. 5). 
(2) Foveolaria orbicularis, n. sp (Pl. XXIII. fig. 4). 
(3) Foveolaria tubigera, n. sp. (Pl. XIV. fig. 4). 
(4) Foveolaria faleifera, n. sp. (PL XV. fig. 6). 
1. Membranipora, Blainville. 
Membranipora (pars), Blainv., Johnst., Auctt. 
Eschara (pars), Pallas. 
Flustra (pars), Linn., Lamk., Lamx., &c. 
Discopora (pars), Lamk. 
Annulipora, Conopeum, Cellepora , Amphiblestrum (sp.), Gray. 
Cellipora (pars), d’Orb., Hag., &c. 
Marginaria, Eoemer. 
Character. — Zoarium encrusting, adnate, calcareous or subcalcareous ; zooecia quin- 
cuncially or serially disposed in transverse rows or irregularly ; no internal calcareous 
lamina. Operculum incomplete. 1 
The genus Membranipora, even as here restricted, includes so many species that it 
becomes advisable to subdivide it into sections. I am acquainted, either actually or by 
published descriptions, with between thirty and forty living species, to which no doubt 
copious additions remain to be made. I have thought it would be convenient, therefore, 
to arrange them in two sections with nearly equal numbers in each, and distinguished 
respectively by the artificial character of having or not having marginal spines. 
1 The term incomplete is applied to au operculum whose lower border is membranous and more or less ill defined. 
