108 G Canadian Arctic Expedition, 1913-1918 



red beneath. The type, as figured from life, was 6 inches (150 mm.) across the 

 tentacles in expansion; diameter of body, when contracted, about 4 inches (100 

 mm.) 



The largest specimens that I have seen, considerably larger than the one 

 described, came from the collections of the U.S. Northwest Boundary Survey. 

 They were dredged in Puget Sound. The type described and figured was from 

 Port Townsend bay, in 30 fathoms. 



Professor McMurrich (op. cit., 1901, pp. 28-34, PI. 1, fig. 6) has described 

 similar specimens, in alcohol, from Puget sound, and he referred them to U. 

 crassicornis, finding them, as to anatomical characters, like the latter. But I 

 think he did not fully appreciate their different appearance in life. It often 

 has happened that no apparent differences in internal anatomy can be found for 

 distinguishing species that are perfectly distinct, in various other classes of 

 animals, as well as among actinians, (e.g. species of Sagartia among Aetinaria). 

 Therefore most of his specimens, if not all, may have been of this species, especi- 

 ally the variety that was found living buried in sand. But it is possible that the 

 true U. crassicornis may also occur in Puget sound, as well as in Alaskan waters. 



McMurrich stated that some of his specimens had bands on the tentacles. 

 The column of his arenicolous variety was bright red, "like a tomato- baked 

 in bread crumbs," and had sand attached to the suckers. Prof. McMurrich 

 examined my drawings, now described (see his note, op. cit., p. 31) and noted 

 the colours, etc. and stated that they represented a specimen "evidently the 

 same as the arenicolous variety" described by him. 



The exposed specimens that he described were either uniform red or orange- 

 brown. He found much variation in the number and size of the suckers, owing 

 to different states of contraction, but in nearly all the cases described they 

 were evidently more numerous and more notable than in our Atlantic U. crassi- 

 cornis. 



He found considerable variations in the form and structure of the sphincter 

 muscle. His specimens were decamerous with irregularities in the fifth and 

 sixth cycles. He found from 81 to 104 pairs of mesenteries. 



The notable variations in the form of the sphincter muscle, partly due to 

 variable contraction, are such as to preclude the use of this feature as a reliable 

 means for distinguishing allied species in this group. Among the Puget sound 

 specimens McMurrich found the lamellae of the sphincter usually arranged in a 

 palmate manner, but in one case in a pinnate form (see his fig. 6, PI.' I). In 

 this the form of the section was obovate, being one-third longer than broad. In 

 east coast crassicornis it is often broader than long. 



He found the longitudinal muscles of the tentacles entirely mesoglceal, 

 and the mesenteries of the first and second cycles were sterile in the specimens 

 examined. 



Having studied many hundreds of living specimens of U. crassicornis, 

 coming from numerous localities and various depths, I have never seen any 

 from the Atlantic coast, having a similar colour pattern, or the same abundance 

 and prominence of the papilliform suckers. Therefore I believe it should be 

 considered a distinct species, even if the sphincter muscle and mesenteries are 

 much alike. It is obvious that the form and size of those muscles must vary 

 greatly according to the amount of contraction. They have also been found to 

 vary even in different examples of a species from the same locality and preserved 

 in the same way. 



With our present knowledge, it appears that some of the internal organs 

 are about as variable as the external colour, etc. At any rate it is unsafe to 

 rely entirely on sections of alcoholic specimens, variously contracted, for the 

 separation of allied species of a genus, or for uniting them. Living specimens 

 must be consulted, as well as internal structure, to determine the real status of 

 actinians. 



