68 Mr. H. N. Moseley on the [Nov. 25, 



Eugosa show an arrangement which may well be compared to the di- 

 stinction of dorsal and ventral regions in Alcyonaria. The most important 

 distinctive character of the Eugosa appears to be the occurrence in them, 

 alone of all Anthozoa, of intracalicinal gemmation *. 



"With regard to Sarcophyton, the fact that compound colonies composed 

 of multitudes of zooids, combined with a lesser number of sexual polyps, 

 occur amongst the Alcyonidse, as well as amongst the Pennatulidae, in 

 which they are so well known from Kolliker's great work, appears to be 

 new to science. That in such colonies and in Heliopora the " Dorsal- 

 facher " are all turned towards the axis of the colony and directed upwards 

 is also a new fact. The zooids in their structure seem to conform very 

 closely to those of Pennatulids (Sarcophyllum, e. g.) ; but to the list of 

 distinctive differences between the zooids and polyps of Pennatulids 

 given by Kolliker, viz. the absence in the zooids of tentacles, the 

 presence of two mesenterial filaments (the dorsal ones), the absence of 

 generative organs, and the shortening of the hypogastric region to such 

 an extent that it fuses with the anastomosing canal- system — to these 

 marks of distinction must be added, in the case of the zooids of Sarco- 

 pliyton, the fact that four of the mesenteries, the dorsal and ventral 

 pairs, are deeper than the others. 



It seems extremely difficult to reconcile the extraordinary succession 

 of the mesenteries in the development of the Zoantharians, discovered 

 by Lacaze-Duthiers, with the facts presented by Alcyonarians. Did the 

 development of the eight mesenteries of Alcyonaria correspond with 

 that of the first eight mesenteries formed in Actiniadae, the first mesen- 

 teries formed would be either the lateral dorsal or lateral ventral ; but 

 these are those which are most rudimentary in the zooids of Sarcophyton. 

 Moreover the mesenterial filaments of the two lateral pairs of septa are 

 in the development of Actiniadse the first to appear, and not the dorsal, 

 which are longest in the Alcyonarian polyps and most persistent in the 

 zooids. Apparently, however, development in Alcyonarians follows a 

 different course. 



In Hcdysceptrum, the development of which has been examined by 

 Kolliker, the eight mesenteries appear from the very first. In Kalliphobe 

 (Busch), one of the Edwardsice, according to Metschnikoff, the larva has, 

 in its earliest stage, eight tentacles and two mesenterial filaments. 



The peculiarities presented by the StylasteridsD have struck many ob- 

 servers. M.-Edwards and Haime placed these corals (Stylasteracea) 

 under the Oculinidae. Gray, however, established a family (Stylasteridae) 

 for the genus Stylaster alone. Pourtales, who in his 'Deep-Sea Corals' 

 dwells upon the many peculiarities of the corallum of this family, places 

 under it the genera Allopora, Stylaster, Distichopora, Cryptohelia'f, Lepi- 



* An examination of the Comulariadas, the only recent solitary Alcyonarians, might 

 very possibly throw light on the question of the affinities of the Eugosa. 



t Pourtales has remarked that the genus Endohelia of M.-Edwards and Haime 



