REPORT ON THE ANTIPATHARIA. 45 



from each other by a mesogloeal septum, so that on the zooidal surface of the 

 branch there is no tissue which with justice can be considered ccenenchyma. The 

 tentacles are arranged in pairs, those situated at each end of the sagittal axis having 

 an unusual situation. In this genus the zooid appears to clasp the sclerobasic axis to a 

 greater extent than in other genera ; thus whilst the lateral pairs of tentacles arise 

 from the peristome, that in the sagittal axis is inserted at a very much lower level, 

 apparently at a point corresponding with the centre of the sclerenchyma. Thus in 

 profile view the ectoderm of the oral cone extends as a relatively flat plate towards the 

 lateral tentacles, but at each end of the long axis of the mouth becomes suddenly 

 depressed and follows the contour of the sclerenchyma to the middle line, and then 

 becomes evoluted to form the sagittal tentacles (PI. IV. fig. 4). 



The zooid is much compressed vertically, though not so much as in Aphanipathes. 

 The tentacles are fleshy fusiform processes, but frequently in preserved specimens become 

 much contracted. Those in the sagittal axis appear to be longer and thicker than the 

 others, as is the case in Leiopathes glaberrima. There are ten mesenteries present, which 

 have a similar arrangement and relative length to those of Aphanipathes, &e. The 

 stomoda3um is elongated in the sagittal axis, and the ectoderm clothing its inner wall 

 is thrown into irregular folds. Some little distance below the oral aperture these folds 

 become very complex, and form on each side an elongate branched tubular process, the 

 inner walls of which have the same structure as the inner wall of the stomodseum, with 

 which they are continuous. These convolutions occupy a position which in the main is 

 parallel to the sagittal axis of the zooid, and possess a lumen which opens into the 

 stoinodreum. 



SCHIZOPATHIN/E. 



The genera forming the subfamily Schizopathina? differ from all other Antipathidas 

 in a most important point — the fact that the zooids are dimorphic. The mode 

 in which this dimorphism is brought about will be best understood by a comparison 

 with the arrangement of parts in Parantipathes larix. In this species the great elonga- 

 tion of the zooid along the axis of the branch, i.e., in the transverse axis of the zooid, 

 leads to a corresponding increase in the length of the transverse mesenteries. In this, 

 as in all other genera of Antipathidse, the transverse mesenteries are the only ones which 

 bear reproductive organs. In the Schizopathinse the elongate zooid becomes divided by 

 two involutions of the peristome into three sections, a central one containing the stomodajum 

 and one at each end in which the reproductive organs are situated. These three sections 

 may remain close together or may become separated from each other by a considerable 

 interval. In reference to their apparent functions, the names gastrozooid may be given 

 to the central zooid, and that of gonozooid to the one on each side of it. The secpuence 



