208 ACTlNl.i: OF ALHATKOSS EXLM.OKATIONS M'MURKICH. 



ill fact all the forms with abiioniially sliapc^l teutai*h'>s,ex('lu(liii<i thosoin 

 which tlu'so stnu'turos are reilmcd to stoinidia, are essentially iiihab 

 itaiitls of shallow water. Perhaps aii explanation ot the development 

 of fronds as in the riiyllaetida' and of branching and nodulose tentacles 

 in shallow -water forms nmy be found in the greater or less mimicry 

 of the plant forms, with which littoral actinians are associated, which 

 is thus produced, and which would serve as a protection i'lom carniv- 

 orous enemies. 



As with the <;eoj;raphical distribution, however, much yet remains to 

 be done before any proper <;eneralizations as to the sij;niticance of and 

 the causes which govern the bathymetrical distribution ot the Actini- 

 aria can be made, and the remarks here i»resented are simply a sketchy 

 outline of some of the ideas that have suggested themselves during the 

 investigation of the Albatross collection. 



May, JS02. 



APPENDIX. 



Since the iireceding report was completed I have had the opportunity 

 of examining the collections of Actinians in the museum at IJerlin, 

 and also the Clialhuffcr collection in the Natural History J)epartment 

 of the British Museum, and must express my sincere thanks at this 

 earliest opportunity to Prof, von Martens and Prof. JetVrey JJell for the 

 courtesy with wliich they acceded to my request to examine these very 

 valuable collections and for their great k'uduess in attording me every 

 fiicility for studying them. I also desire to state my obligations to my 

 friend Prof. A. C. Haddon for nuiuy valuable suggestions and nnich 

 interesting information with regard to the European Choiulracdnina', 

 as well as for the opjwrtuuity of examining the valuable collection of 

 forms belonging to that grou]) which he possesses. 



As the result of my studies of these collections 1 have been able to 

 contirm the correctness of certain suggestions made in the report, and 

 also have obtained new light upon the identilication of certain forms, 

 and have thought it advisable to incorpcu'ate in this l\eport in the form 

 of an appendix some of the more important of my results. 



An('moni<( rariahilis (p. 147). — In the Berlin INFuseum are i)reserved the 

 forms described by Studer ('78), which were collected by the (iazcllo 

 exiK'dition, and among them is a fcnni which seems to be identical with 

 that descrilx'd al)ove as An(>)ioni(i rariahilis. This is Corj/)ia<'tis n(r>if<(, 

 Studer. in size and habitat it agrees very closely with the Alhutross 

 specimens, and the capitate character which Studer describes for the 

 ti'iitacles is not at all well ])ronounced. It was upon this character 

 that Studer relied in assigning it to the genus Corymictis, but the ten- 

 tacles are plainly arranged in cycles, a fact which may be deduced from 

 his statement that the tentacles are "zahlreich in zwei Keihen." The 

 similarity is so striking that, taking it iijto consideration with the fact 

 that both have the same habit, and come from essentially the same 

 locality and depth, I have no hesitation in pronouncing for its identity 



