178 M.Valenciennes on the Gorgonidse. 



less resemble the Actinite so abundant on the coasts of all seas, 

 characterized by their simple, conical, hollow tentacles, and by 

 the numerous ovigenous lamellae which rise in their internal 

 cavity. The second order, to which M. Milne-Edwards has long 

 since given the name of Alci/onia — fixing the zoological meaning 

 of this word, borrowed from Pallas, which has been applied by 

 other authors to the most dissimilar creatures — includes those 

 polypes in which the mouth is surrounded only by eight pin- 

 nated tentacles, and in which there are only eight internal ova- 

 rian lamellae ; each tentacle is a conical tube, furnished on each 

 side with shorter, filamentous secondary tentacles, which are 

 inserted on the primary tentacle in the same manner as the 

 barbs of a feather upon the stalk. All these polypes are united 

 posteriorly to a common sarcoid body, forming true compound 

 animals. This soft tissue, which is often gelatinous in its ap- 

 pearance, is consolidated by numerous calcareous concretions, 

 entirely composed of carbonate of lime, and possessing deter- 

 minate forms in each species, but often very different in differ- 

 ent species, and also frequently exactly similar in very distinct 

 species belonging to different genera. They must not be con- 

 founded with the spicules or acicules which also exist in the 

 tissue of several parts of the polypes, principally round the oral 

 orifice, or near the cells through which the body of the isolated 

 animal is exserted. To these bodies I give the name of sclerites. 



The masses produced by the aggregation of the Alcyonia are 

 as varied in their form as the polypidoms of the Anthozoa, which 

 have received the general name of Madrepores. The compound 

 Alcyonia are sometimes protected by a simple epidermic scleren- 

 chyma, without any solid internal parts ; but sometimes there 

 exists an axis, which is variable in its nature, form, and chemical 

 composition. 



Amongst the families established in this order by MM. Milne- 

 Edwards and Dana, the family to which the latter has given the 

 name of Gorgonida, and which has been divided by Milne- 

 Edwards into several subfamilies, includes the species united by 

 Pallas in the genus Gorgonia. 



A work which I have long been occupied with, upon the nu- 

 merous species of Sponges, has led me to compare their spicules 

 with the sclerites of the Gorgonida. The examination of these 

 corpuscles has enlarged the sphere of my obsci'vations, and some 

 new researches have become the basis of a new classification of 

 these zoophytes. 



All my predecessors, with the exception of M. Milne-Edwards, 

 only describing the Gorgonidce from dried specimens, have 

 founded their characters upon the arrangement of the divisions 

 ol' the more or less delicate branches of what they call the axis of 



