no THE CRAG POLYZOA. 



DiASTOPOHA MEANDRINA, S. Wood, Anil. N. H,, xiii, p. 14. 



D. EUDESIANA, M. Edioards (?), 1. c. p. 33, pi. xiv, fig. 1. 



DiTAXiA COMPRESSA (?), Goldfuss ; Hogenow, Maast. Kreideb., p. 50, pi. iv, fig. 10. 



MesenteripopvA neocomiensis (?), B'Orbigny, Terr. Cret. 



Habitat— C. Crag, S. Wood; 7. 8. B. 



Another fossil species, M. Michelinii, Blainville, might be suggested as synonymous 

 with the above, but as this is figured and described as having the foliations not anasto- 

 mosing, I have not placed it even doubtfully in the list. Of the species given above with 

 a mark of doubt, perhaps Ditaxia compressa of Hagenow, = (?) Blast. Eudesiana of 

 Milne-Edwards, affords the nearest resemblance to the Crag form. But this may arise, 

 perhaps, merely from the circumstance that they are the most correctly drawn figures, for in 

 the absence of figures conveying a sufficient idea of the general habit, it is impossible to 

 determine their identity or not with M. meandrina. 



As in several other Cyclostomata, more especially of those belonging to the present 

 family, the moiiths of the tubes in this species are eventually closed with a calcareous 

 lid, having, usually, a minute central perforation. 



Genus 5. Tubulipora, Lamarck. 



Polyzoario decumbente, plerumque adnato, integro aut diviso, e puncto excentrico pro- 

 cedenti. Cellulis superne liberis, ascendentibus, infra coalitis. 



Polyzoarium adnate or decumbent ; entire, or divided into lobes or branches ; cells 

 partially free and ascending, radiating from an excentric point. 



Tubulipora (pars), Lamarcic; Blainville : Milne-Edwards; Johnston; Lonsdale; Michelin; 

 Reuss, &c. 

 — Lamouroux ; Hagenow, Maast. Kreid. 



Ceriopora (pars), Hagenoiv, Gein. Grundr. 

 Phalangella (sp.). Gray, Append. List. Brit. Rad., p. 149. 

 Obelia (pars), Gray. 

 DiASTOPORA (sp.), M. Edwards. 

 Criserpia (?), M. Edwards. 



Under the genus Tubulipora are here understood species in which the polyzoarium is 

 sometimes closely adnate, sometimes affixed only by the base and simply decumbent, or 

 else partially erect, and in which the tubes, though immersed at the base, are, in the perfect 

 state, free for a considerable part of their length. The growth of the polyzoarium com- 

 mences at a single cell or a pair of cells, whence it radiates so as to form either a flabelli- 

 form entire expansion, or one subdivided into irregular lobes or into linear branches ; the 

 point of origin being, however, always marginal or distinctly excentric, by which circum- 

 stance it is distinguished from that of the closely allied genus Patinella (nob,), in which the 



