AFFINITIES AND ZOOIOGICAI POSITION 67, 



this step, so far as I am aware, Is to be found in the account 

 of the development of the MonticttliporcE as given by Lind- 

 strom, and I have above stated the reasons which prevent 

 me from accepting that account. Apart from this, the chief 

 grounds for placing Monticulipora among the Polyzoa seem 

 to be based upon its resemblance to the genus Heteropora, De 

 Blainv., which is a familiar Secondary and Tertiary fossil type, 

 and of which at least two living species are now known to 

 exist (see Waters, Journ, Roy. Micr. Soc, vol. ii. p. 390, 

 PI. XV., 1879; and Busk, Journ. Linn. Soc, vol. xiv. p. 724, 

 PI. XV., 1879). Under these circumstances, it will be advis- 

 able to append here a description of the external and internal 

 characters of the genus Heteropoi'a, so as to enable some con- 

 clusion to be formed as to the extent and validity of any affini- 

 ties which may subsist between it and Montiailipora, D'Orb. ; 

 and I am enabled to do this with some advantage, as I possess 

 specimens of one of the recent species of the genus (viz., the 

 form described by Prof. Busk under the name of H. neozelani- 

 ca, which name seems to be really only a synonym of the pre- 

 viously recorded H. pclliculata, Waters), and as I have submit- 

 ted these specimens to a careful microscopical examination by 

 means of thin sections,^ the results of which have been pub- 

 lished elsewhere (Ann. Nat. Hist., sen 5, vol. vi. p. 329, 1880) 

 and are here reproduced. 



The genus Heteropora Is thus defined by Professor Busk in 

 his classical * Monograph on the Fossil Polyzoa of the Crag ' 



(1859):- 



*' Polyzoarlum erect, cylindrical, undivided, or branched ; 



surface even, furnished with openings of two kinds ; the larger 



representing the oi'ificcs of the cells, and the smaller the ostioles 



of the interstitial canals or tubes." 



^ Mr Waters informs me, in a leUer, that having examined specimens which I 

 had sent him, he is of opinion that H. neozelanica, Busk, is identical with his pre- 

 viously described H. pelliculata. This conclusion is doubtless correct ; but as Mr 

 Waters has not yet published his view, and as Professor Busk has therefore had no 

 opportunity of expressing a revised opinion on this point, I continue in the mean- 

 while to use the former name for my specimens. 



