324 PROFESSOE P. M. DUNCAN ON THE 



I described shortly, in the report on the ' Porcupine '-Expedition Madreporaria\ two 

 species, Amphihelia atlantica and Amphihelia ornata. Both of these forms have 

 columella ; and one is striated on its wall, and the other is not. 



In examining a specimen of DiploJielia profunda, Pourtales, dredged up by Pourtales 

 in deep water off Bahia Honda (324 fathoms), I was much surprised, not only at 

 its resemblance to some of the results of the No. 54 dredging, first expedition of 

 ' Porcupine,' but also to the Amphihelians with striated walls. 



Lately M. Sars has sent me a specimen of the Madrepora ramea of Miiller, from 

 off the Norwegian coast, found in moderately deep water. It is an Amphihelia like 

 Seguenza's A. mioccenica and my A. ornata; and as it has an older date of publication, 

 it must have precedence, and these and others be absorbed under the title of Amphihelia 

 ramea, Miiller, sp. 



Now there is no distinction between Diplohelia profunda, Pourtales, and Amphihelia 

 ramea, Miiller, sp., and the first-named species must be absorbed. 



What are the distinctions between Amphihelia and Diplohelia 1 Diplohelia, Milne- 

 Edwards & Jules Haime, op. cit. vol. ii. p. 120, is differentiated as follows : — " Le 

 polypier est dendroide et presente dans les parties inferieures un coenenchyma bien 

 developpe. Les calices affectent sur les rameaux une disposition alterne distique. 

 La columella est spongieuse et bien developpee. II n'existe pas de palis. Les cloisons 

 sont purement dentelees et debordent a peine la muraille." 



Some of the species have granular walls, and others striated walls; and it will be 

 readily observed that it is impossible to distinguish between Seguenza's and Miiller's 

 species of Amphihelia and the Diplohelim, except on the plea that the species of the 

 last-named genus have the septa finely toothed. 



A careful examination of many specimens of Amphihelice has proved to me that the 

 tertiary septa are often toothed in some corallites, and not in others of the same branch. 

 The presence of a columella in the very numerous specimens of Amphihelia oculata and 

 of A. ramea (which now includes the species already noticed) proves that the presence 

 of one in Diplohelia is no differentiation. The absorption of Diplohelia by AmphiJielia 

 I consider necessary under our existing knowledge. 



Diplohelia^ meneghiniana, Seguenza, D. doderleiniana, Seguenza, D. gismondiana, 

 Seguenza, D. profunda, Pourtales, are varieties of Madrepora ramea, Miiller, or 

 different parts of the same corallum possessing gemmative variation, as they all do. 



All these striated Diplohelim become classified under the species Amphihelia ramea, 

 Miiller, sp. (syn. Madrepora ramea). 



The diagnosis of the genus Amphihelia by MM. Milne-Edwards and Jules Haime is 

 not quite consistent with observations which those excellent authors could now make 

 upon numerous and well-preserved specimens. Nor is my assertion, made in the Report 



' Proc. Eoyal Society, March 24, 1870. 

 ' Seguenza, op. cit. pp. 488, 489. 



