78 THE CRAG POLYZOA. 



1. H. iMBELLis {n. sp.) PI. IV, fig. 6, and PI. X, fig. 7. 



Polyzoario convoluto ; cellulis ovatis, subumbonatis ad marginera presertim punctatis ; 

 ostio semicirculari, labio inferior! recto peristomate simplici. 



Polyzoarium convolute ; cells ovate, punctured especially round the border, subum- 

 bonate in front ; orifice semicircular, vf\\h a straight lower border and simple peristome. 



EscHAKA PEKTUSA (?), Micheliti, \. c, pi. Ixxix, fig. 2. 



Fragments of this species may be confounded with Eschara cornuta, Lep. variolosa, and 

 L. Jiaimeseana, and perhaps of E. pertusa, although little attention will suffice for their dis- 

 tinction. 1. The species is not adnate, although one layer overlies another. 2. From E. 

 cornuta and L. variolosa it is distinguished by the unarmed orifice, whilst the absence of 

 an introral denticle, and the presence of an umbonal projection on the front of the cell, 

 distinguish it from L. Haimeseana. 



§§§ 3. Libera. 

 Fam. VII. SELENAEIIDM Busk, 1853. 



Polyzoarium liberum orbiculare seu irregulare, conicum sive depressum, supra con- 

 vexum, infra planum vel concavum ; facie convexa tantum cellulosa. Cellulis duplicis 

 generis seriatim dispositis seu quincuncialibus. 



Polyzoarium free (?), orbicular or irregular, conical or depressed, convex on one side, 

 and plane or concave on the other ; composed of a single layer of cells, usually of two 

 kinds, which open on the convex surface only, 



SELENARiADiE, Bush, B. M. Cat., pt. ii, p. 97, 1852. 



EscHARiD^ (pars), B'Orbigny, Ann. d. S. N., 3d ser., xvii, p. 284, 1852. 



PoLYPiERS roBAMiNES (pars), Lamarck, An. S. Vert., 2d ed., ii, p. 299. 



Cellari^ea (pars), Blainville, Man. d'Actin., p. 448. 



MiLLEPOR^ES (pars), Lamoroux, Exp. Meth., p. 44. 



AsTERODisciNA, Lonsdale, Dixon's Geol., Sussex, p. 159. 



Originally included by Lamarck among his " Polypiers foramines," a heterogeneous 

 group, containing also several genera of Foraminifera and true Corals, and by Lamouroux 

 associated also with Foraminifera and some Corallines, in the order " Milleporees," the 

 true systematic position among the Polyzoa, of the Sclenariidae or Lunulites, was first 

 indicated by Dc Blainville ('Man. d'Actinol.,' p. 448, 1834), who placed them at the head 



