6 THE VOYAGE OF H.M,S. CHALLENGER. 



the tentacles are replaced by appendages of a different value, for instance, by stomidia 

 in the Liponemidae which I have described, or by bushy or arborescent growths in 

 the families Sarcophianthidse and Thalassianthidas erected by Andres. On the other 

 hand, there are forms in which more tentacles than one correspond to a mesenterial 

 chamber ; accessory tentacles, placed on the oral disc, being present in addition to the 

 primary tentacles. This is conclusively proved only for species of Corallimorphus, but 

 Andres has rendered it excessively probable also for species of Corynactis (compare the 

 account of Corynactis ? sp. ? p. 10, infra). For such forms I have instituted the family 

 Corallimorphidse, Andres the family Corynactidse. I believe that my designation 

 deserves preference, because it is the older, and because my diagnosis of the family 

 alone insists upon the important anatomical characteristic ; on the other hand, I concede 

 to the Italian naturalist that the family may be restricted to species with knobbed 

 tentacles, and that all Actiniae with modified tentacles, of which an accurate investigation 

 is still required, may be brought under a series of further families. 



For a comprehension of the above discussion, I give a view of that arrangement of 

 Hexactinian families which I hold the most advantageous, in the form of a synoptic 

 table. 



A few changes have been made in the English terminology used in the former part 

 of this Eeport : " oesophagus " has been replaced by " stomatodseum," " mesoderm " 

 by "mesogicea," and "oesophageal groove" by " siphonoglyphe, " ' 



