GENERA OF FAVOSITID&. 181 



mentary vertical lamellae. The corallites differ from one an- 

 other in size and shape, and are so amalgamated by their walls 

 that no distinct lines of demarcation can be distinguished be- 

 tween them " [" elles se soudent ensemble et forment des murs 

 confluents, de sorte qu'on ne peut pas les distinguer les unes 

 des autres "]. 



Obs. I am not acquainted with any example of this genus, 

 and can do nothing more than give the above translation of 

 M. Eichwald's description of it. For the clearer understanding 

 of its characters I have likewise reproduced Eichwald's figures 

 (PI. VII., figs. 3 - 3 b], which, if reliable, would seem to indi- 

 cate a distinct generic type. These figures present us with a 

 ramose corallum, with a general resemblance to the dendroid 

 forms of Pachypora or Favosites ; with very thick-walled coral- 

 lites, which are furnished with a small number of strong mar- 

 ginal septa (PI. VII., fig. 3 a). The drawing given on PL 

 VII., fig. 3 b, is said by Eichwald to be the " coupe transver- 

 sale," and it doubtless is the transverse section ; but it repre- 

 sents the outermost portion of such a section, where the tubes, 

 as they diverge outwards, become nearly horizontal, so that 

 we really see the corallites cut longitudinally. In this section 

 we see that the tubes in accordance with the description given 

 by Eichwald are intersected by thick tabulae, placed at cor- 

 responding levels in contiguous tubes. 



There is nothing in Eichwald's description or figures which 

 would lead to any safe conclusion as to the systematic position 

 of Laceripora ; and no allusion whatever is made to the exist- 

 ence of mural pores. I have therefore provisionally included 

 the genus in the Favositidce, simply in deference to the opin- 

 ion of Dr Lindstrom, who is probably acquainted with actual 

 examples of the genus, and who states that it is " nothing more 

 than a highly-perforated Favosites " (Ann. Nat. Hist., ser. 4, 

 vol. xviii. p. 12, 1876). 



The only known species of the genus is the Laceripora crib- 

 rosa of Eichwald, which is stated to occur in the "grauwacke" 

 (Upper Silurian), and also in the Carboniferous formation. 



