1848.] LONSDALE ON FOSSIL ZOOPHYTES. ^^ 



places assigned to it in general classifications* cannot be accepted 

 now, whatever may have been their value at the time of proposing. 

 Under this want of satisfactory guidance it is merely suggested that 

 the lower greensand genus should be considered as inferior in com- 

 position to the lameliated, so far as the want of vertical plates within 

 the abdominal cavity is concerned, lea-sdng to future discoveries the 

 determining an approximate, right position. 



The fossil which next claims attention appears to have been originally 

 named ^5^;-^a elegans, sp. n.f It consists (PI. IV. fig. 12) of closely 

 approximated, abdominal cavities or stars, with more than twelve un- 

 equal lamellae; the bottom of the cavity is a simple, transverse lamina, 

 more or less crossed by the four most prominent lamellae (fig. 12*), 

 but no central union of these plates was detected, nor any reti- 

 culated central structure : the stars have no definite outer boundary, 

 the lamellae of one cavity frequently blending with those of the ad- 

 jacent hollows (fig. 12*): internally (fig. 13) the abdominal cavities 

 present a succession of laminae, varying in range, curvature and incli- 

 nation, and are sometimes intersected by vertical plates ; while be- 

 tween them is a coarse cellular reticulation : additional cavities wathin 

 the area of a specimen occur between the pre-existing. 



The only figured coral, known to the describer, which exhibits an 

 apparently similar combination of external characters, is the Astrcea 

 alveolata of M. Goldfuss, found in the Jura-Kalk of Wurtemberg 

 (Petref. p. %^. tab. 22. fig. ?>)X\ ^^^ ^^ internal structure is neither 

 alluded to nor repre-sented. The flat, simple flooring of the cavities 

 resembles however very closely that of the Atherfield fossil ; and its 

 great dimensions are opposed to the inference of its being the upper 

 end of a solid central axis : in the limited, imvard range of the lamellae, 

 there is also an accordance, as well as in their outward blending ; but 

 the comparison cannot be extended. Prof. Goldfuss' s species has 

 been removed by M. de Blainville to his own subgenus Siderastrtea § ; 

 it is therefore necessary to inquire, first, in what respect the lower 

 greensand zoophyte differs from AstrcBa^ its original generic assign- 

 ment ; and secondly, if it possesses the characters of M. de Blain- 

 ville' s subordinate group. 



i. Astrcea was one of Lamarck's great dismemberments from the 



* Consult Lamarck, 2nd Ed. t. ii. " Polypiers areseau," pp. 210, 212 and 286- 

 also de Blainville, Man. d' Actinol. " Les Millepores," pp. 400, 401 and 404. 



t Quarterly Journal Geol. Soc. vol. iii. p. 296, Aug. 1847. M. Goldfuss has 

 described under the same designation a Maestricht coral (Petref. p. 69, pi. 23. fig. 6 

 -6 d) ; subsequently removed by M. de Blainville to the genus Ileliopora {op. cif. 

 ante, p. 393). In the Transactions of the Geological Society of London, 2nd ser. 

 vol. iv. pp. 204 and 351, 1837, Dr. Fittou notices the existence of an Astrrea at 

 Atherfield Point, possibly the fossil under consideration. 



X M. Michehn, in describing his greensand coral Astrcea cribraria, found at 

 Avignon, notices a seeming agreement with Ast. alveolata, but he states that the 

 lamellae, in fully exposed ca\*ities, extend to the centre. (Iconographie Zoophyte- 

 logique, p. 21, pi. 5. fig. 4.) 



§ Man. d'Actinol. p. 371, Ast. Siderastrcea cavernosa ; and 2nd Ed. Lamarck 

 t. ii. p. 421, No. t45. 



