of llin UnijOHa to the. licin<j ZoantheLC. 393 



ami counter septa of the Rugosa ; also some such relationship 

 may perliaps hold between the complete (macrotype) or 

 incomplete (microtype) sixth protocnemic pair and the en- 

 larged or diminutive alar septa. The presence of a gonidial 

 groove at one extremity of the sfomodjenm in the Zoantliids 

 and its absence from the other border still further conform 

 \\'\\\\ the marked difference between the two extremities in 

 tlie liugose coral (cp. figs. 8 & 12). 



The ontogeny of Lo'phop'yUum proUferum, both in its 

 primary and secondary phases, is thus in fullest agreement 

 with the history of living types known to the actinologist — 

 not, it is true, with any coral type, but with a group of the, 

 closely related Actiniaria. So far as Lophopkyllum can be 

 taken as a representative, the peculiar septal plan of the 

 Kugosa introduces no new conception into Anthozoan studies, 

 and any other peculiar features which the order possesses, 

 such as tabula3 and vesicular endotheca, are of very subordinate 

 morphological imj)ortance compared with the septal scheme. 



A comparison of the septal ])lan in L. proliferum with the 

 numerous figures of Zaphrentoid corals given in the works of 

 Ludwig and Kuiith reveals a unity of arrangement in very 

 many cases, and from the scanty evidence yet adduced there 

 is no reason to suppose that the primary septal plan was in 

 anyways different from that here establislied, though in many 

 cases actual proof may not be fortiicoming. Kunth every- 

 v,here assails the hexamerism of Ludwig, yet he nowhere 

 ])roduccs direct evidence of a primary tetrameral condition ; 

 indeed, 1 have not come upon any figure by any author 

 representing a section of a primary four-rayed condition in 

 the Tetracoralla. The converse is, however, true. Both 

 Duncan (1867) and Kunth (18G9), apparently independently, 

 have found certain species of the Palaiozoic Jleterophyllia lo 

 be primarily hexamerous. As a result of this tlie former 

 writer connects them with the Mesozoic and recent AstrjeidaB, 

 though acknowledging that certain of their other characters 

 ally them to the Cyathophyllidae. There now seems every 

 reason to suppose that the primary hexamerism of IJetero- 

 pJtyllia is to be associated with that of Lophophyllum and that 

 the subsequent development follows the same essential plan 

 in both. It is impossible to accord the same treatment to 

 Lojihophyllum as that to which Ileierophyllia has been sub- 

 jected ; HI the former the addition of tlie metasepta according 

 to Kunth's law effectually prevents any suggestion of an 

 Astra?an character. Considering how universal is the hexa- 

 meral protocnemic stage in modern corals and anemones, it 

 would not be surprising to find it a fundamental characteristic 

 of the Madreporaria of Paheozoic times. 



