Scientific results of explorations by the U. S. Fish Commission Steamer Albatross. 



I l'iil)li.s)ir(l l)v j)cri)iisHi()ii of lion. Marshall .McDonalil, ( 'oiiiiniHsioiMM- of KinlinricH. | 



No. XXIII.— KErUKT ON TlIK A(rriNLK COLiJlCTKl) MY 'IMIK IJNITKl) 

 .STATKS FLSir COMMLS8ION STEAMER A LHA'I'ItOSS I^IIK'INC; TiiE WINTER 

 (JV 1887-1888. 



I!V 



J. T'l.AYi'AiK McMiiKKicri, M. A., I'ir. I). 

 [Willi IMaf.s .\i.\-.\xx\ . ] 



The- collection which foiins the subject of this icpoit was forwarded 

 to me soon afr.er its arival in Wa.sliiii.<;toii, and I j;'la<lly availed myself 

 of the opportunity thus presented of coiitinuiM<;- tln^ iuvesti^atioii of 

 tlie d«'ep-sea Actiniaiis, wliich was so admirably inaugurated by Prof. 

 Iiichard Ilertwig. The studies of this distin^^uished naturalist hav(^ 

 r(!sulted in the establishment of a new and more correct basis for the 

 classification of the A(;tinia'!, by calling- to the aid of the somewhat un- 

 certain external peculiai'ities, the more reliable characl<'ristics rev<'ale(l 

 by a thorou<;li anatomical study of each species. The revision of the 

 A(!tinians in accordanc<'- with this new system of classilicati(»n founded 

 by I'lof. Ilertwij;' has becMi carri<Ml on by myself ibr the Actinia' of th«i 

 West Indies and by l*rof. JIaddon for the forms occurring- on the coasts 

 of (Ireat IJritain. Much has been added to <mr knowledge of many 

 foiins, and many errors have been corrected, and it has been my hope 

 tliat the i)resent study woidd clear away still further th(^ mists that ob- 

 scure the relationshi])S of the various Actinian groups. 



The present r(;port deals with the 10<lwardsia', Protactiniai, Ilexac- 

 tiiiia', aii<l(Jeriaiithea' ol)tained by the yl//>^//ro.s'.v. I h<)]M' in a- fnture 

 report to give the residts of my studies of th<^ Zoanlhea'. 



I gladly acknowledge the many courtesies I have nuieived from my 

 IVieiid, Mr. Iiichard llathbun, during the prei)aration of this report. 

 I am indebted to him Ibr tiie oi)portunity of comparing scveralspecimens 

 in the collection with allied and occasionally identical forms obtained 

 by tiie Fish Commission steamers off the eastern coastof North Ameri(!a. 



Part I. 



THE CLASSIFICATION OF THE ANTHOZOA, AND ESPECIALLY OF THE ACTINIA. 



Wliat may be termed an approximately correct idea of the relation- 

 ships of the various groups of animals now included under the term 

 Anthozoa or Actinozoa,can be said to have come in only with the begin- 



Proceedings Kational Museum, Vol. xvi— No. 930. 



119 



