MR. A. W. WATERS ON FOSSIL LITHOTHAMNIA. 245 



at different times. The recent ones have perhaps most 

 often been placed among the corals, while the fossil forms 

 have passed most frequently as concretionary. 



Lamarck, Deshayes, Milne -Edwards, D'Orbigny, Bronn, 

 and others placed the Nulliporse among the Anthozoa, 

 either as a separate genus or as a division of the Mille- 

 porse. Ehrenberg placed them under his Pocillopora, but, 

 while doubtful what is their true nature, does not think 

 they are plants. Blainville and Link consider them to be 

 concretions ; and such the fossil forms have usually been 

 considered to be by geologists. Murchison and Sedgwick, 

 speaking of the limestone of Wildon, Styria, from which 

 place a few of those on the table were collected, say, 

 " many of the masses have a mottled appearance, resulting 

 from a number of spheroidal and cylindrical concretions 

 formed of concentric layers of white carbonate of lime, 

 probably produced, in the first instance, by organic bodies, 

 the traces of which are now lost." 



In 1837 Philippi*, by microscopic examination of some 

 recent forms, proved their vegetable nature, establishing 

 nine species of what he called Lithothamnium, and placed 

 them near to Corallina. Kutzing, later, entirely confirmed 

 their vegetable nature, calling them Spongites. 



In 1866 Rosanofff published a classical paper on the 

 Melobesiacese, which he divides into three sections — 

 Melobesia, Lithophyllum, and Lithothamnium. In this 

 paper he gives full descriptions as to their mode of growth 

 and their reproduction. 



Philippi, Kutzing, and Rosanoff confined their attention 

 to the recent forms. Unger, of Vienna, in 1858 J proved, 

 by microscopical examination, the similarity of organisms 

 of the Leithakalk. 



* Wiegmann's ' Archiv fur Naturgeschichte,' iii. Jahrg. 1837. 



t Mem. de la Soc. Imp. des Sc. Nat. de Cherbourg, t. xii. 



I Denk. der Ak. der Wissensch. math.-naturw. CI. Bd. xiv. (Wien). 



