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ACTINOLOGICAL STUDIES. 



I.— The MESENTERIES and (ESOPHAGEAL 

 GROOVES of ACTINIA EQUINA, Linn. 



By Joseph A. Clubb, M.Sc. (Vict.), 



Victoria University Scholar in Zoology ; 

 Assistant Curator of the Derby Museum, Liverpool. 



With Plate XX. 



[Read May 13th, 1898.] 



Up to comparatively recently external characters alone 

 served as a means of identification and as a basis for the 

 classification of the Anemones, and thanks to the work 

 of Prof. E. Forbes, P. H. Gosse and others, we have 

 excellent accounts of the external appearance and habits 

 of our British Actinians. But latterly, the attention of 

 investigators has been directed more and more to the 

 details of the internal anatomy, as forming a sounder 

 and more scientific method of arriving at a true under- 

 standing of the natural relations of this group of animals. 

 The brothers Hertwig, by the publication of their paper 

 on the Anatomy of Actinians (1879), have done much to 

 bring this about, and later, Dr. Richard Hertwig, in his 

 Report on the "Challenger" Actinians (1882), laid 

 down lines of classification based entirely on anatomical 

 characteristics. In 1889 Prof. Haddon published Part I. 

 of a "Revision of the British Actiniae," in the introduction 

 to which he makes the statement that " apart from 

 external characters, we are unable to assign to most of 

 them (the British species) a position in the groups pro- 

 posed by Prof. R. Hertwig, on account of the absence of 



