158 IV. I. Robinson, 



g-eographical distribution of the coral stocks, a principle also 

 insisted upon by Neumayr (1889). The work of Duerden and 

 Brown seems to indicate that the origin of Hexacoralla is not 

 a direct one from Tetracoralla, while the work of Faurot, 

 Carruthers, and the author has brought out a similarity in the 

 early ontogenetic history in the two groups that is perhaps more 

 easily explained by a theory of direct descent. This question 

 will be discussed on later pages (i 61-195). 



