1848.] LONSDALE ON FOSSIL ZOOPHYTES. 81 



the type of the group. Ast. Sid. cactus was removed to Pavoniahj 

 Ehreiiberg, who obtained Hving specimens in the Red Sea {/oc. cit.), 

 on the borders of which Forskal procured the coral originally, but in 

 a semi-fossil state* (De Bl. p. 3/0). 



Ast. galaxea is a well-known coral, and the animal has been de- 

 scribed by Lesueur {op. cit. p. 285, pi. 16. fig. 13), who also states 

 that Ellis and Solander's figure (tab. 47. fig. 7, or Lamx.) is "tres 

 bien faite." More than one species of possibly distinct genera have 

 however been included under the term A. Sid. galaxea. Lesueur states 

 that his West Indian coral is non-tentaculated, whereas MM. Quoy 

 and Gaimard have referred to the same specific name a New Holland 

 zoophyte found by themselves, the polypes of which had apparently 

 white tentaculesf . Specimens supplied by an experienced London 

 dealer in natural history as Ast. galaxea, and which differed not to 

 the unassisted eye from Ellis and Solander's figure, afforded the fol- 

 lowing structures. Small abdominal cavities of variable form, having 

 at the base a bladder-Jike lamina or a series of minute projections : 

 lamellae numerous, knife-shaped, frequently but not regularly grouped 

 in threes, edges serrated ; in their outward range the lamellae of ad- 

 jacent cavities sometimes unite and constitute apparently continuous 

 plates : spaces between them crossed by roundish bars which divide 

 the intervals into a quadrangular network, the meshes penetrating 

 deeply downwards ; where the lamellae of adjacent cavities coincide, 

 the bars assume the appearance of a continuous line ; but where the 

 plates are disconnected, there is often a crenulated structure. In a 

 vertical section, the lamellae present broad, perpendicularly continuous 

 plates imperforated except towards the axis of the coral ; but they are 

 beset with longitudinal rows of large papillae, the broken extremities 

 of the bars, and they are occasionally crossed by delicate irregular 

 laminae, the fractured edges of the bladder-like structure. The cen- 

 tral axis is nearly solid, and composed of the union of the broadest 

 lamellae ; the whole interior of the cavity, except that occupied by the 

 living digestive organs, being traversed vertically by lamellae and cross- 

 wise b}'' the bars. The young stars are wholly produced in the net- 

 work without the area of the mature. A. careful comparison of these 

 characters with the structures of Ehrenberg's Astrcece or Favics will 

 lead to the conclusion that Siderastrcea galaxea may be assumed as 

 the type of a true genus ; and the compiler of these memoranda has 

 long possessed another well-distinguished species. It is not possible 

 to compare the leading component parts of the recent coral with 

 those of the twenty-eight fossil species. Siderastrrea cristata has 

 similarly papillated lamellae (consult Goldf. pi. 22. fig. 8c), but the 

 aggregate of structures appears to be different, while in Sid. clathrata 

 (Goldf. pi. 23. f. I) there is no resemblance whatever. Confining 

 the attention, however, to Ast. or Sid. alveolata (Goldf. pi. 22. f. 3), 



* Ehrenberg describes the animal as wanting tentacula {loc. cit); and Mr. 

 Dana, in his account of Pavonia, states, that " when alive and expanded, the ten- 

 tacules appear as mere inflations of the exterior membrane around each polype 

 mouth, and are extremely short." — Expl. Exped., Zoophytes, p. 320. 



t Miine-Edwards, 2nd Ed. Lamarck, t. ii. p. 418, 

 VOL. y^ PART I, G 



