234 BRITISH NULLIPORES. 



The opinion of Ellis was tlien adopted by all naturalists ; 

 and even when Lamarck proposed to separate the Nulli- 

 pores from the true Millepores, he did not entertain any 

 doubt of their polypiferous character. Schweigger, in 1819, 

 was perhaps the first who gave distinct expression to his 

 doubts of this creed.* When in fact we compare the struc- 

 ture of these presumed polypidoms with any undisputed mil- 

 lepore, the difference is at once seen to be very considera- 

 ble ; for pores can always be perceived on the surface 

 of the latter, and the interior is distinctly cellular, while 

 neither on the surface nor in the interior are there any 

 traces of cells in the Nullipores. These, on the contrary, 

 consist of solid concentric layers of cretaceous matter laid 

 over each other very much in the manner they are in the 

 stalactite. Their apolypous character may indeed be con- 

 sidered as proven. It is very true that they contain a cer- 

 tain quantity of organic matter, but this, according to Blain- 

 ville, may be deposited simultaneously with the calcareous 

 ingredients, and so incorporated into the mass. Thus, then, 

 in De Blainville's opinion, the Nullipores are a kind of 

 stalagmites deposited in places where the sea is not liable 

 to be frequently agitated, and where its bottom and banks 

 are formed of calcareous rocks. Such was the doctrine 

 taught long before by Borlase, in his Natural History of 

 Cornwall ; and Olivi was likewise disposed to concur in 

 this mechanical explanation of their origin. It has been 

 also adopted by Link, the celebrated Professor of Botany 

 at Berlin. He says — " Olivi and Bertoloni think that the 



" Schweigger's definition of his genus Nullipore is — " Stirps irregu- 

 laris e gelatina animali prorsus lapidescente. Polypi nulli." Handb. 

 p. 412. 



