The Actiniae of the Plate CoUectioh. 271 



to consist mainly of this process and to be attached to the raesentery 

 by a very narrow base. The parieto-basilar muscles are not very 

 strong althongh tliey form a fold lipon the surface of the mesentery. 

 The oral stomata are small but the marginal ones are very large 

 and may occnpy almost one-half the width of the larger mesenteries. 

 Acontia were numerons. No reprodnctive organs were found in the 

 individuals examined. 



This species is particularly interesting as showing the ocurrence 

 in one of the Actininae of a peculiarity hitherto known to exist 

 only in the Stichodadylinae (e. g. Ricordea florida) and in the Chorals. 

 The existence of a multiplicity of stomatodaea denotes an imperfect 

 division and although cases of this have been observed in Metridium, 

 yet it cannot be considered a normal occurrence in that genus and 

 does not proceed farther than the formation of a second month; it 

 may, indeed, represent only a stage in a complete division. In the 

 present species the imperfect lission is evidently a normal occurrence 

 and is furthermore peculiar in that there are invariably produced 

 a number of small peripheral stomatodaea in addition to two or 

 more central ones. It would seem ab first sight that the peripheral 

 mouths had been formed in situ and not by a Separation of portions 

 of an original central stomatodaeum. but I am inclined to believe 

 that this is not the case, but i-ather that the original stomatodaeum 

 was polyglyphic, the majority of the siphonoglyphs and small neigh- 

 bouring portions of the stomatodaeum having separated at an early 

 stage, carrying with them their own directives and one or two pairs 

 of neighbouring mesenteries. The reasons for this belief are, first, 

 that occasionally small mouths are found in close relation to the 

 larger ones (see text-flgure A), having probably separated later than 

 the others, and, second, that if the small stomatodaea had formed 

 independently of the large ones it might be expected that their 

 mesenteries would be limited to the level of the stomatodaea, but, 

 on the contrary, there are just as many mesenteries in the lower 

 part of the column, below the level of the stomatodaea, as there are 

 in the upper part, and, furthermore, they are arranged below with 

 reference to the larger stomatodaea, the smaller subordinate groupings 

 being confined to the upper part of the column entirely. In default 

 then of definite embryological observations to the contrary it may 

 be assumed that the various stomatodaea have resulted by a number 

 of incomplete fissions. 



