Acti7iaria g 105 



The colours, also, are very variable. The body-wall is usually more or less 

 red, varying from pale red or pink to bright red, crimson, and dark red, often 

 streaked or blotched with hghter and darker red, or in the case of littoral speci- 

 mens, with blotches of dull olive green or dark red on a brownish red ground- 

 colour. McMurrich (op. cit., 1910, PI. 1) has well figured this littoral colour- 

 variety. More rarely the body-wall is flesh-colour or pale pink, or even yellowish- 

 white. The disk is nearly always Ughter-coloured, and marked by conspicuous 

 double lines of bright red or crimson radiating from the mouth to the bases of 

 the tentacles, which they enclose, as in fig. 13 of Plate XX. These markings 

 are very characteristic of the species and are seldom lacking. The tentacles 

 are nearly ahvays annulated with bands of red and white, or they are red with 

 one or two bands of white. 



The specimen figured on PI. XX, fig. 13, from life, had the body bright 

 cherry-red, blotched with paler red, ancl with pale red suckers; disk flesh- 

 colour with crimson radiating lines and deep red lips; tentacles bright red 

 with a median band of white and a white or p>ink tip, and a V-shaped lavender 

 or pale lilac-coloured mark near the inner base, running down to the base as 

 a narrow line. 



The specimen figured on PI. XIX, fig. 4, from life, was flesh-colour, streaked 

 with a very light red, and the tentacles were very pale red, with a subterminal 

 band of white, but the red radial lines of the disk were distinct. This example 

 was over 6 inches (150 mm.) across the expanded tentacles. 



The sphincter muscle is very large, roundish, and cord-like, or well circum- 

 scribed, often appearing oval, reniform, or subcordate in a cross section, (PI. 

 XXVI, fig. 7) with the radiating lines of muscle fibres very numerous, fine, 

 and dichotomously branched. The proximal ones are arranged pinnately; 

 the distal ones in a palmate manner. 



The mesenteries of the first three cycles may all be perfect and many of 

 them may be fertile, though those of the first two cycles are often sterile. The 

 perfect mesenteries have a longitudinal muscle, on the inner half, with branching 

 supports, but becoming very thin on the outer half. The mesenteries of the 

 fourth and fifth cycles are imperfect and mostly fertile. Prof. McMurrich 

 (op. cit., 1910, pp. 65, 66, PL ii and iii), has well described and figured the 

 sphincter muscle and mesenteries. Hargitt (op. cit., 1914, figs. 3, 4) has also 

 figured them. 



The form of the sphincter muscle, as seen in cross sections, varies a great deal, 

 largely due to the various states of contraction and modes of preservation, but 

 also according to the age. 



The arrangement of the mesenteries, which are very numerous in large 

 examples, as well as of the tentacles, is most often strictly decamerous, but 

 hexamerous and octamerous specimens are not uncommon. Two well developed 

 siphongylphs and two pairs of directive mesenteries are usually well developed. 

 Numerous pairs of perfect mesenteries of about three cycles are present and 

 like most of the imperfect ones may bear gonads, except the directives. Large 

 specimens may have five cycles, the fifth cycle often incomplete. 



Eggs are retained in the body-cavity until they develop into well formed 

 red young, with two or more cycles of tentacles. 



This species is circumpolar, extencHng down on the Eastern American coast to 

 Nantucket Shoals, Block Island and Watch Hill, RT., and Fishers Island sound 

 It has been found off Alaska and British Columbia on the west coast, and 

 perhaps in Puget sound. On the European side it reaches England and perhaps 

 the Mediterranean as U. coriacea} It was taken in Bering strait^and the 

 adjacent Arctic Ocean in considerable numbers by the North Pacific Exploring 

 Expedition (1852-56), as recorded by me in 1867. 



■ According to Carlgi'en (1902), this torm is a distinct species. More verrucose, etc. 



