224 Chriatmas Island. 



thin wall, which extends downward through the corallum, cutting 

 it up into well-defined quadrangular or polygonal corallites. This 

 wall is more definite internally than is the case in P. gaimardi. 

 The species belongs to the group of which P. arenosa (Esp.) is 

 a convenient t}^e ; that form differs, however, by its larger 

 columella and more regular and equal septa ; the corallum is said 

 to be thin and encrusting in typical form of arenosa, though that 

 point is probably unimportant. 



In one specimen (I^o. 6, figd. Fig. 7) the walls are tunnelled 

 by some boring alga. 



Montipora, aff. danse, Edwards & Haime. 



Manopora tulerculosa {non Lam.), Dana, 1848. Zoopli. : Expl. Exp. "Wilkes, 



vol. viii, p. 507, pi. xlvii, fig. 2. 

 Montipora dance, Edwards &; Haime, 1851. Mon. Porit. : Ann. Sci. nat., Zool., 



ser. Ill, vol. xvi, p. Qb. 



Mr. Andrews' collection includes a specimen of a massive 

 Mo7itipora, with caliccs 'GS mm. in diameter, separated by 



Fig. 8. 



ccenenchyma of about the same width, and with six well-developed 

 septa, and usually some representatives of the second cycle. In 

 these characters it agrees with 31. dance. Specimens of the genus 

 do not appear to have been previously met with as fossils. 



The specimen (No. 364) was collected in the first inland cliff 

 on the south from "West White Beach at alt. of 120 feet. 



