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On 
DESCRIPTION OF CHALK CORALS. 2E 
Tab. XVIII. figs. 29 to 33. 
Very few extinct, articulated corals have been noticed by naturalists. Scilla', 
Walch’, Parkinson®, and other palzontologists have described more or less fully, 
as well as figured, the well-known fossil to which Goldfuss* has applied the term 
Isis Melitensis, but for which Schlotheim® apparently proposed and perhaps at 
an earlier date the designation Isis pileatus. Goldfuss® enumerates also another 
tertiary species Is. reteporacea, considered however by M. Milne-Edwards’ to be 
a very doubtful determination ; M. De Blainville® has likewise assigned the ap- 
pellation Js. breviarticulata to a Kentish zoophyte, stated by Guettard? to be truly 
‘“‘un coralloide articulé ;” and the latter authority” figures another body “a trois 
branches, qui sont comme articulées a leur origine.” Lastly Sir C. Lyell”, in 
his memoir on the cretaceous and tertiary strata of Seeland and Moen, has de- 
lineated a ‘coral allied to Isis from the limestone of Faxoe.” Of these extinct 
Anthozoa Is. Melitensis alone can be brought into direct comparison with the 
English chalk fossil, the others being insufficiently described and figured so far 
as the compiler of this notice is aware, specimens being also unattainable ; and 
in conducting the inquiry, it will be requisite in consequence of M. Goldfuss’s 
determination, to mention briefly the leading characters of recent species of Isis. 
That genus, as limited by Lamarck’*, Lamouroux”, and later authorities, con- 
sists of an axis composed of calcareous segments united by horny intervals or 
“internodes” of less diameter ; the whole being invested by a friable, perishable 
crust, easily detached from the axis, and the visceral cavities are wholly confined 
" De Corporibus Marinis, &c., ed. 1759, p. 63. tab. 21. f. 1; first published in Italian in 1670, La 
vana speculazione, &c.: consult also Scheuchzer’s copies of Scilla’s figures, Herb. Diluv., edit. 1723, 
p- 79. no. 194. tab. 14. f. 1. 
* Naturgeschichte der Verst. Knorrischen Sammlung, &c., Dritter Theil, p. 194. Supp. tab. 6 f- 
figs. 6,7; 1771. 
* Org. Rem., vol. iii. p. 72. pl. 8. f. 2.4.7, 1820-24. Parkinson alludes also to a Calne oolitic fossil 
as referable to Isis, p. 73. 
* Petrefacten, &c., p. 20. tab. 7. figs. 17, 1826-1833. 
* Systematisches Verzeichniss, &c., p. 19, 1832, published after Schlotheim’s death. The catalogue 
includes three other species of Zs¢s; but it is impossible to determine the nature of the bodies so de- 
signated without further assistance. 
° Op. cit. p. 99. pl. 36. f. 4. 7 Lamarck, 2nd edit. tome ii. 477. Observations 1836. 
* Man. d’Actinol., p. 503, 1830-34. * Mémoires, &c., tome iii. p. 520. pl. 58. f.5, 1770. 
Op. cit. p. 493. pl. 41. f. 4. 
" Geol. Trans, London, 2nd series, vol. y. p. 249. fig. 5, 1838. 
© Op. eit. tome ii. p. 473. '* Exposition Méthodique, p. 39. 
Pea 
