EEPORT ON THE ACTINIARIA. Ill 



The correlation, which exists in all Actiniaria between the oesophageal grooves and 

 the directive septa, is also shown in the Zoanthess, for there is only one oesophageal 

 groove, whilst the other is wanting, in correspondence with the rudimentary nature of 

 the directive septa to which it should belong. The tentacles, on the other hand, are 

 equally developed and placed in two circles, the inner of which belongs to the intra- 

 septal spaces, the outer to the interseptal spaces. 



All the characters taken into account by former naturalists iii the diagnosis of the 

 Zoanthese are of subordinate value when compared with the peculiar conditions just men- 

 tioned. The animals are united into colonies either by means of branched stolons or by 

 means of a broad basal plate, but there are also solitary forms which are embedded 

 with their rounded aboral ends in the sand like the Edwardsise. The entire surface of 

 the wall is often permeated with foreign bodies, though in many specimens such encrusta- 

 tions are wanting completely. Finally, the canals, which make their way from the 

 ectoderm into the wall, where they become branched and connected into plexuses, are 

 confined to certain forms only. 



In the division of the Zoanthese I agree chiefly with Verrill, who divided the 

 species forming colonies into four genera ; Mammilifera, Zoantlms, Palythoa, and 

 Epizoanthus. The former two are distinguished from the latter by the absence of sand 

 encrustations. Zoantlms and Epizoanthus are distinguished from Mammilifera and 

 Palythoa by the fact that in the former two the polyps project plainly above the common 

 basis, whilst in the latter two they are united up to the free end by the basal coenen- 

 chyma. I have restricted the family Zoanthidse to those genera which form colonies, 

 and have associated all those which are solitary under the name Sphenopidse. 



Family Zoanthid^. 



Zoanthese forming colonies ; the individuals of a colony connected with one another 

 by endodermal canals, which run out from the gastric space at the lower end of each 

 polyp. 



Zoanthus, Cuvier, pro parte. 



Zoanthus, Verrill. 



Zoanthidse without sand encrustations and with a slightly developed coenenchyma 

 consisting either of a plexus of stolons or of a thin plate ; the single polyps projec 

 to a considerable height above the coenenchyma. 



Zoanthus, sp. (?) (PI. XIV. figs. 1-4 and 6). 



Habitat. — Bermuda Islands. 



Dimensions. — (Of the individual polyps): height, 0'1-1'3 cm. ; breadth, 0"l-0"4 cm. 



