98 G Canadian Arctic Expedition, 1913-1918 



Actinauge borealis. New species. 

 Plate XXIV; Figures 1-lh. 



Among the Hudson bay actinians were two specimens that seem to belong 

 to an undescribed species resembling Actinauge rugosa externally, but having 

 much longer tentacles which lack the large basal lobe usually seen in that genus, 

 and differ in other ways. 



Both specimens are very strongly contracted, so that the internal organs 

 form a compact mass. The longer invected tentacles reach to and In-low the 

 base of the long stomodseum, or quite to the basal disk in some cases. 



The column-wall is firm, strongly wrinkled both longitudinally and trans- 

 versely; it also has vertical rows of low, but persistent, verrucse. The whole 

 surface below the capitulum is covered with a firmly adherent, thin, dark coloured 

 eipdermal coating, much as Phellia. The capitulum is strongly invected, but 

 sections show that it is covered by numerous raised ridges, with ;. plain edge 

 toward the margin, but thickened and crenulated toward the parapet. 



The verruca on the parapet are not much more prominent ihan those 

 below, and have the same structure. 



The tentacles are numerous, up to 84 to 96, slender, the inner ones nearly 

 as long as the column; they are so crowded by contraction that they M<- angular 

 in sections. 



The stomodseum is elongated with the walls strongly plicated. Two siph- 

 onoglyps are present. 



The sphincter muscle (Plate XXIV, figs. 1, la) is mesogloeal and very well 

 developed. In transverse sections, made near the oral disk (figs. lb-ic) and 

 including some of it, there are about 24 to 40 perfect mesenteries, which are 

 all very much alike, with strong retractor muscles extending nearly across their 

 whole breadth. 



Between these perfect mesenteries there are pairs of small, narrow ones, 

 which bear gonads. A little lower down there are twelve pairs of perfect mesent- 

 eries; and below the middle of the stomodaeum there are only six pairs. They 

 are sterile (fig. If). All the other mesenteries bear dense clusters of gonads and 

 filaments, squeezed compactly together by the severe contractions of the walls. 



Between every pair of mesenteries there is a narrow, angular, raised endo- 

 dermal ridge (r, r,) which appears triangular in the transverse sections. These 

 occur of larger size and less acute between the primaries, and are very small 

 between those of the fourth and fifth cycles (fig. If). 



The ectoderm (figs, le, If, h, h) is moderately thick and firm, with deep 

 grooves caused by wrinkles, and containing more or less of the dark epidermal 

 coating, and with thickened places caused by the verruca (figs. Id, Ig, v, v). 



The mesoglcea is much thicker than the ectoderm and endoderm. com- 

 bined (le, Ig, h, h). It is crossed by numerous very fine, nearly straight, muscu- 

 lar lines, running out from the endoderm at nearly right angles, often more than 

 half way across. In some sections they are bent a little in zigzag forms. 



None of the original colour remains except a tinge of light red on the retracted 

 oral part of the disk and upper part of the mesenteries (fig. 1, m). 



The contracted specimens are nearly cylindric and higher than broad. 

 The larger one is 25 mm. high; 13 mm. in diameter; length of the longer retracted 

 tentacles 22 mm.; outer shorter ones, about 10 to 12 mm. 



These two specimens came from Richmond gulf, east side of Hudson bay, 

 in 25 fathoms, August 24, 1920, obtained from Eskimos by F. Johansen. 



The generic position of this species seemed a little doubtful. It looks 

 much like some species of Phellia, but differs in having a verrucose wall and a 

 ribbed capitulum. From typical A ctinauge it differs chiefly in lacking notable 

 basal tentacular lobes and in having very long slender tentacles. However, a 

 careful examination shows the basal lobe on some of the less powerfully com- 



