III. 



The Actinaria of the Canadian Arctic Expeditions, with Notes on Inter- 

 esting Species from Hudson Bay and other 

 Canadian Localities. 



By A. E. VERRILL 



Professor Emeritus, Yale University 

 (With thirteen plates and nine text figures). 



Only a few specimens of Actinians were received by me from the Canadian 

 Arctic Expedition, 1913-18, besides a few larval forms, belonging to a Cerianthus. 

 One specimen is of interest because it is in process of dividing by fissiparity. 

 Three species of Actinians of considerable interest and not previously known 

 from Hudson bay were obtained by Mr. F. Johansen in 1920. Others were 

 collected there by Dr. A. P. Low. Three species from Hudson bay are now 

 described as new species. 



In addition, I have thought it best to include a number of little known 

 species, from both coasts of Canada, that need revision, and especially those 

 from the rich fauna of the fishing Banks off Nova Scotia and Newfoundland. 

 But this article is not intended to include a complete list of the Banks species, 

 though it includes most of those commonly found there. 



The drawings from living specimens were mostly made by Mr. J. H. Emerton. 

 I am much indebted to Professor Alexander Petrunkevitch of Yale University 

 for the pains he has taken in making for me photographs from several difficult 

 subjects figured in this part and the preceding part of this report. Several 

 of the anatomical drawings in each article were made by Mr. A. H. Verrill. 



Order ACTINARIA 

 Family SAGARTIAD^E Gosse. 



Actinians usually with numerous retractile tentacles, and always having 

 acontia and normally cinclidse. Acontia may be emitted from the mouth as 

 well as from cinclida. Column variable, either without suckers or with suckers 

 or verrucse. Sphincter muscle is usually mesogloeal and more or less diffuse, 

 or it may be in two parts; rarely it is more or less endodermal. Mesenteries 

 are usually hexamerous, but they may be pentamerous, decamerous or irregular. 

 Often only 6 to 12 pairs, including directives are perfect down to the bottom of 

 the stomodaeum, and the six primary pairs are nearly always sterile; more 

 pairs may be adherent to the stomodseum near the oral disk, and sometimes 

 for its whole length. Variations from this normal arrangement are frequent. 

 There may be two siphonoglyphs and two pairs of directives in the more normal 

 species, but some species of Sagartia, Metridium, etc, may have only one siphon- 

 oglyph and one pair of directives, as often as two pairs, or there may be three 

 or more pairs and corresponding siphonoglyphs. Such variations are believed 

 to be due to their asexual modes of reproduction. See below under Met 



Among the eastern American species that have such notable variations are 

 Sagartia (Thoe) lucice Verrill, and S. spongicola Verrill, and Metridium dianthus. 

 (See McMurrich, Zool. Bulletin, Vol. 1, No. 3, 1897). Among English species 



