256 TABULATE CORALS. 



Chcztetes among the Actinozoa, it becomes abundantly clear 

 that we have no sufficient data upon which to found a final 

 conclusion. All that can be said is that the genus seems to 

 have nearer relationships with the Halysitidce and Tetradiida 

 among the Palaeozoic " Tabulata " than with any others, and 

 that we may therefore suppose, with some probability, that it is 

 really an ancient type of the Alcyonaria. 



Still greater difficulties surround the attempt to definitely 

 fix the place of the Monticuliporidce in the zoological system. 

 Within late years there has been a strong tendency among 

 palaeontologists to relegate the fossils in question to the Polyzoa, 

 and a good deal of evidence some of which will be referred to 

 subsequently has been brought forward in support of this 

 view (see especially the admirable paper by Dr Lindstrom on 

 the affinities of the Anthozoa Tabulata in the ' Annals of 

 Natural History,' 1876). The chief ground for the proposal 

 to refer Monticulipora and its allies to the Polyzoa is found in 

 the resemblance between the ramose Monticulipora and the 

 Polyzoan genus Heteropora, De Blainv., and it must be ad- 

 mitted that the mere general likeness between these two types 

 is extremely close. External similarity, however, is an unsafe 

 guide in dealing with questions of zoological affinity, and such 

 evidence as I have at present in my hands leads me to believe 

 that there is in reality no relationship beween Monticulipora 

 and Heteropora. The latter of these types is best known as 

 occurring in the Tertiary deposits as a fossil, but I possess a 

 large and well-marked recent form from New Zealand, nearly 

 allied to H. pustulosa, Busk, and H. tortilis, Lonsd., which I 

 have submitted to Mr Busk, and which this eminent authority 

 has pronounced to be new. In this interesting species, as in 

 the extinct forms of the genus, the polyzoary is ramose and 

 calcareous (fig. 34), and consists of long, tubular, thin-walled 

 cells, which radiate from the imaginary axis of the branches to 

 open on the surface by round apertures. The walls of the cells 

 appear to be imperforate, though in some forms of the genus 

 (H. l&vigata, D'Orb.) they are pierced by minute foramina ; 



