^SournaiKM^s^^^^^ "^^F^ Micvoscoincal Societij. 79 



Naturelle des Corallaires ' made its appearance, giving, in addition 

 to an introduction to the organization of the Actinozoa, a systematic 

 classification and description of the Alcijonaria, Actinaria, and 

 Antijpathidge. In treating of the Alcijonaria, however, it is a 

 matter of extreme regret that, except for a passing reference to the 

 results arrived at by Valenciennes, no attention was paid by Milne 

 Edwards, nor any value attached to the important histological cha- 

 racters afforded by the structure of the calcareous spicula which 

 so abound in the sclerenchyma of this group. 



For the latest, and without question the most important work 

 that has yet appeared on the subject. Science is indebted to Pro- 

 fessor A. K5lliker, who in a monograph entitled " Die Bindersub- 

 stanz der Coelenteraten," in his ' Icones Histiologicae ' for 1866, 

 enters fully into the modifications of the hard structures which 

 obtain throughout the sub-kingdom, and devotes upwards of two 

 magnificent quarto plates to the representation of the calcareous 

 spicula of the Alcyonaria alone. He modifies to a considerable 

 extent the plan of grouping into genera pursued by Milne Edwards, 

 adopting in a great measure, as his foundation for doing so, the 

 variation of form of the respective spicula. The results arrived at 

 by Kolliker are principally based upon his examination of the type 

 specimens of Esper and Duchassiang and Michelotti. 



The study of a large series of spicula in my owa possession, pre- 

 pared from the type specimens of Valenciennes contained in the 

 Paris Museum, the comparison of these with a similar collection in 

 the Museum of the Koyal College of Surgeons, together with the 

 examination of a fine series in the same museum derived from other 

 sources, and lastly, the consultation of the collections of dried spe- 

 cimens both in the College Museum and in the British Museum, 

 has enabled me, in addition to corroborating to a great extent the 

 results arrived at by Professor Kolliker, to add testimony of my own 

 regarding a number of species not referred to in his veiy excellent 

 monograph, as likewise to refer to their true zoological position 

 numerous species of Valenciennes of whose affinities Milne Edwards 

 stood in doubt. 



Before proceeding to further details, a brief outline of the system 

 of classification of this order now most generally accepted, including 

 the organisms which form the subject of this present communication, 

 will obviate the necessity of future repetition. 



This order, the Alcyonaria, belongs to a sub-kingdom, the Coelen- 

 terata, of which the Sea-anemone, the Fresh-water Hydra, and the 

 Jelly-fish are the most familiar and instructive types. 



The Alcyonaria are Anemone-like Coelenterates, which, in their 

 normal condition, invariably possess neither more nor fewer than 

 eight tentacles, which are without exception to a greater or lesser 

 extent pinnate. 



