1 30 THE CRAG POLYZOA. 



seem, after inspection of specimens derived from the Lamouroux Collection, characterises 

 the genus as follows : " Cellules subpolygonales, petites, poriforraes, irregulierement dis- 

 posees, et occupant le bord superieur et cxterne de cretes ondees, sinueuses, lisses d^un 

 cote, plissees d' I'autre, constituant un polypier calcaire, globuleux ou hemispherique, 

 divergeant de la base u la circonference." 



It is probable, that in drawing up this character, the learned author had in 

 view not so much, if perhaps, at all the Apsendesia cristata of Lamouroux, as two other 

 forms associated by himself with it, and which would appear to constitute, as it seems to 

 me, two distinct genera-, or at any rate one. These species are A. dianthus, Blainv., and 

 A. cerebriformis, Blainv. The former derived from the Jurassic beds at Caen, and pro- 

 bably really representing the Ap. cristata of Lamouroux ; and the latter procured from 

 the tertiary beds of Anjou, and which, in all probability, is the same as Fascicularia 

 aurantimn, Milne-Edwards, of the Crag. 



Lamouroux describes his genus Theonoa as constituted of a massive, conical or coarsely 

 cylindrical, undulated, simple or lobed polyzoarium, whose surface is covered with nume- 

 rous holes or deep depressions, very irregular in their form and disposition, and not 

 perforated at the bottom, whilst the intermediate, raised portions of the surface are occu- 

 pied by the openings of the cells. 



This account would point at some resemblance in structure, perhaps, between 

 Theonoa and Fascicularia, but in the absence of more precise indications with respect 

 either to Apsendesia or Theonoa, it seems better to adopt the appropriate appellation sug- 

 gested by Milne-Edwards, and since employed by several geological writers, in preference 

 to either of the older terms. 



L Fascicularia tubipora {n. sp.) PI. XXI, fig. 1. 



Cellularnm fasciculis distantibns, cylindraceis, septis transversis, concentricis, pari 

 intervallo distantibus, connexis. Superficie polyzoarii tuberosa, tuberibus cancellatis, 

 interstitiis glabris, areolisque hexagonis ornatis. 



Tubes assembled into distinct cyUndrical bundles, united at uniform distances apart 

 by horizontal, tabular, concentric laminae; surface -covered with rounded eminences, upon 

 which the cells open uniformly all over ; intermediate surface smooth, and marked with 

 hexagonally reticulating lines. 



Habitat.— C. Crag, S. Wood; J. S. B. Red Crag ?, ;S'. JF. 



The masses formed by this species, which seems to be very abundant, vary in size 

 from one inch or less, to upwards of six in diameter. When worn smooth on the surface, 

 and covered, as is often the case, with an adlierent layer of sand, they look like 

 anything else than what they are. In this condition it is next to impossible, in many 



