648 Haddon and Shackleton — A Revision of the British Actinice. 



by Mac Andrew in Loch Fine, W. Scotland, in 1844. Thompson records it as 

 having been dredged by himself and Hyndman in 1835 and 1846, 15—20 fathoms, 

 from Strangford Lough (N.E. Ireland). Wright and Greene copy this. It may or 

 ma}^ not be this species. We now describe specimens from S. W. Ireland which 

 may possibly be this species : Fischer identifies it from the N. and W. coasts of 

 France. Andres and Pennington merely quote Gosse. 



Bod//-waU (PI. Lix., fig. 4). — The body- wall is extremely thin in this species. 

 The ectoderm, where present, is continuous, and is covered by a thin cuticle. It 

 contains occasional nematocysts. Incrustations, wliich consist chiefly of grains 

 of sand, are fairly numerous. Cell-enclosures are very rare. The endoderm 

 is very thin, and of uniform thickness. The muscular layer is rather feebly 

 developed. 



Sjjhincter muscle. — The single mesogloeal sphincter is well developed, although 

 it is not so powerful as in the free variety of B. incrustatus. It consists of 

 elongated cavities which are well filled with muscle-fibres, the cavities form- 

 ing for the most part a single row (PI. lx., fig. 3). 



Disc and Tentacles. — The structure of the disc and tentacles is for the most part 

 as in other species of Zoanthe£e ; but oval nematocysts. similar to those which are 

 found in the ectoderm of the body-wall and of the oesophagus, are present in the 

 ectoderm of the tentacles of more than one of the specimens which we have cut. 

 We have not, however, found them in all our specimens. 



(Esophagus. — The ectoderm of the oesophagus is thrown into folds which appear 

 to be deeper as a rule in the short than in the longer specimens. There is a well- 

 marked groove. Nematocysts are generally to be found in this region ; but in 

 one or two specimens we have not been able to find them. In some cases they 

 are very abundant. Sometimes they appear to contain black pigment-granules. 

 In other cases they are quite clear, containing a distinct, coiled thread. 



Mesenteries. — The mesenteries present the usual macrocnemic arrangement. 

 The imperfect mesenteries are fairly well-developed. The longitudinal muscles are 

 borne upon mesogloeal plaitings which are frequently well-marked, but in some 

 of our specimens they are much slighter than in others. Nematocysts are very 

 abundant in the ectoderm, which forms the mesenterial filaments in the usual 

 manner. 



Gonads. — We found no gonads in any of our specimens. 



