68 TABULATE CORALS. 



laminae, which for the most part only extend across about a 

 third or a half of the total diameter of the tube. At other 

 times the tabulae are complete, and they are occasionally quite 

 regular and horizontal. Mural pores usually biserial, very 

 closely set, opposite or alternating. 



Obs. This species was taken by Milne-Edwards and Haime 

 (foe. cit.) as the type of the separate genus Emmonsia, distin- 

 guished from Favosites by the peculiar condition of the tabulae. 

 I agree, however, with Mr Billings in thinking that the occur- 

 rence of single examples of this species in which the tabulae are 

 in parts complete, renders the establishment of a distinct genus 

 for its reception unnecessary. Moreover, incomplete, leaf-like, 

 or squamose tabulae are known to occur in undoubted species 

 of Favosites (e.g., in F. Forbesi and in its variety tuberosd). 



Recently, Dr Rominger (foe. cit.) has applied the name of 

 Favosites hemisphericus, Yand. and Shum., to the entirely dif- 

 ferent F. turbinata of Billings ; while he has established a new 

 species, under the name of F. Emmonsii, for the form now 

 under consideration. The only ground given for this change 

 is, that "all the original specimens of Fav. hemisph. kept in Mr 

 Yandell's collection are identical with Favosites turbinatus of 

 Billings." I regret that, after a careful consideration of the 

 circumstances, and with all deference to this high authority, I 

 am unable to acquiesce in the propriety of this change, where- 

 by two species thoroughly familiar to all palaeontologists are 

 made to change places, one of them receiving an entirely new 

 name. This course deprives Milne-Edwards and Haime on 

 the one hand, and Mr Billings on the other, of their just con- 

 nection with two species which they for the first time described 

 in an excellent and thoroughly recognisable manner; and it does 

 not appear to be sufficiently justified by the fact that the speci- 

 mens labelled F. hemispherica in Mr Yandell's cabinet are really 

 referable to F. turbinata, Billings. On the contrary, it appears 

 to me that the just course in such a case as this, is, not to make 

 any alteration in generally accepted and long current names, 

 unless it can be shown by clear evidence that such an altera- 



