Haddon and Shackleton — A Revision of the British Actiniae. 611 



the not unnatural confusion into which the group has fallen, and from which it 

 has, to a certain extent, been extricated through the labours of Erdmann and 

 M^Murrich. In no group is it more necessary to combine anatomical and 

 microscopical examination with the methods of the older zoologists — for the 

 species of Zoanthese can only be established after sections have been cut and 

 studied. The identification of new material with recognized species requires 

 the utmost circumspection. 



It is impossible to determine the genus to which many previously described 

 species belong until the types have been re-discovered, and then submitted to an 

 anatomical investigation. A complete monograph of the group is at present an 

 impossibility. We have, however, ventured as far as we safely could in this 

 direction. 



We have investigated the anatomy of eleven species belonging to five genera 

 of Zoanthese from Torres Straits, besides several other forms, at the same time 

 that we were occupied upon the British representatives. Our Paper on the Torres 

 Straits specimens is published simultaneously with this one, and in the same 

 Journal ; and we would ask those who are interested in this group to study both 

 Papers together, for the two are, to a certain extent, complementary to each 

 other. 



Methods. — All the specimens examined by us were preserved in alcohol, and 

 when a sufiicient quantity of strong alcohol is used this answers perfectly well. 

 We stained the objects whole in borax carmine, imbedded them in paraffin, and 

 cut them with a "rocking" microtome. In a few cases we stained the sections 

 after they were fixed on the slides. 



The unincrusted genera are very easy to cut, and so are some of the incrusted 

 forms, especially some of the species of Parazoanthus. Those wishing to study the 

 anatomy of the group cannot do better than commence with P. axinellce, which is 

 very easily cut by the ordinary paraffin method. It was perfectly unnecessary for 

 von Koch to employ his " Schliff-methode " (Morph. Jahrb, vi., 1880, p. 359) when 

 investigating this species. We mention this solely to prevent others from taking 

 superfluous trouble. The different species of the genus Epizoanthus are, as a rule, 

 difficult to sectionize, on account of the incrustations. U. paguriphilus is, however, 

 practically free from them ; owing to the great thickness of the mesogloea in this 

 species, celloidin is a better imbedding material than paraffin, as heat has to be 

 employed in the latter method. As a rule, the incrustations in Zoanthese from coral 

 seas are calcareous, and admit of being readily dissolved away. We use nitric 

 acid for this purpose. 



The use which we have made of the Papers of Erdmann and M'Murrich 

 will emphasize the indebtedness of students of the Zoanthese to those in- 

 vestigators. References to other workers will be duly acknowledged where we 



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