MivW. Lonsdale on the Genus Lithostrotion. 4-65 



of continued, previous lamellae, than those which are originated 

 in germs. It was impossible to consider this development, with 

 its free semicircular outline and bold wall towards the parent 

 stem, as a condition of the cellular extensions before mentioned, 

 and in which, as already stated, no dividing structure exists : the 

 composition also of the one differs wholly from that of the other. 

 The second example of an addition in L. irregulare agreed in posi- 

 tion, outline, and the existence of a perfectly environing layer 

 with the first; but the structure within its area was not so 

 distinct. Nevertheless, in the middle was a white spindle-shaped 

 spot, possibly an incipient axis; and from the wall, on the 

 straight side as well as the curved, issued rudimentary plates. 

 No doubt was entertained that both these bodies were young 

 corallites ; and from the internal characters of the former, it was 

 inferred that they were not strictly produced from germs, but 

 contained within them partial extensions of structures which had 

 entered into the composition of the parent. No instance was 

 detected of a very early state in offshoots of Litlwd. sexdecimale, 

 but several of a more advanced stage. They were all smaller than 

 the stems to which they were attached; and they had on that 

 side a well-formed straight or curved wall, the concave outline of 

 the latter being adapted to the convex exterior of the old corallite. 

 They had more or less the contour of a horse-shoe, in consequence 

 of oblique intersections ; and around the wall were rudimentary 

 lamellae, the more prominent plates being generally on the side 

 most distant from the parent stem. Other states farther ad- 

 vanced towards maturity were observed in both species ; but they 

 did not require special notice. A direct comparison between the 

 reproductive process above imperfectly noticed, and that in the 

 fossils of Lhwyd and Parkinson, or in the Lithostrotion striatum 

 of Dr. Fleming and the Cyathophyllum basaltiforme of Mr. 

 Phillips, cannot be established from want of information ; nor was 

 the mode detected in the basal tiform corals included in Mr. 

 Sharpens collection. The author is also unable to teat the ac- 

 curacy of his statement respecting the plan in Stylastrea, and re- 

 garding which the ' Archives ' contains the following observation : 

 " La pretendue multiplication par fissiparite signalee par M. 

 Lonsdale, et qui a servi k cet auteur de caractere pour separer 

 cette espece des Lithostrotion, nous semble etre le resultat d'une 

 mauvaise observation." {JLith. ? inconfertum, p. 445.) He re- 

 grets that the grounds for correcting his error are not given; 

 and he only conjectures, that what he believed to be a fissiparous 

 operation, may be regarded by M. Milne-Edwards and M. Jules 

 Haime as due to submarginal, gemmiferous developments. He 

 ventures nevertheless to copy his account of what he noticed, and 

 principally in the Russian coral to which he applied the term 

 Ann. $ Mag. N. Hist. Ser. 2. Vol. viii. 30 



