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XIII. 



EEPOETS ON THE ZOOLOGICAL COLLECTIONS MADE IN TOERES STEAITS 

 BY PEOFESSOE A. C. HADDON, 1888-1889. 



ACTINIA : I. ZO ANTHER. By PEOFESSOE ALFEED C. HADDON, M.A. (Cantab.), 

 M.R.I. A., Professor of Zoology, Eoyal College of Science, Dublin, and MISS ALICE 

 M. SHACKLETON, B.A. Plates LXL, LXIL, LXIII., LXIV. 



[Eead Notembee 19, 1890.] 



The following is the first instalment of an investigation on the structure and 

 systematic relations of the Actiniae collected by one of us in Torres Straits. We 

 decided to publish our account of the Zoanthese first, as it is a well circumscribed 

 group and admits of independent treatment. We took this opportunity of studying 

 the British forms, and have thus had a considerable number of forms under exami- 

 nation at the same time. This has given us a personal knowledge of every genus 

 except Mammilifera, of which genus no authentic specimens exist in any museum. 

 Our account of the British Zoantliese is simultaneously published with this as 

 " A Revision of the British Actiniae," Part II. : The ZoanthejB (Trans. Roj^al Dublin 

 Society, vol. iv., ser. ii.) ; and we would refer the reader to that Memoir for a general 

 summary of the anatomy of the group, and a special account of that of the British 

 representatives. We have also given a classification of the Zoanthese, and as far 

 as is possible have allocated all the species described by other authors to their 

 proper genera. It is impossible at the present time to monograph this group, as 

 there is such a general sameness in external character that it makes it difiicult to 

 seize on points which are of descriptive value. The present confusion in which 

 this group lies is mainly due to this fact ; the fault is that of the animals themselves 

 rather than that of the zoologists who have described and named them. This 

 similarity of appearance not onlj^ affects the species of a genus, but also the species 

 of different genera. Thus it becomes a necessity for every species to be examined 

 anatomically by means of microscopical sections, first to determine its genus, and 

 secondly to discover accurate specific characters. Once a species is thoroughly 



TKANS. ROY. DUB. SOC, K.S. VOL. IV., PART Xnt. 5 E 



