478 Verrill, Notes on Radiata. 



Metridium. Oken. 



Actinia {pars) Linnseus, Lamark, Cuvier, Dana, etc. 



Metridium Oken, Lehrbuch der Naturg., iii, p. 349, 1815, {non Metridium Ehrenberg, 



Dana, Gosse, etc., ^Oulactis). 

 Actinoloba (pirs) Blainville, Diet, des Sci. Nat., 1830 ; ditto, Manuel d'Actinologie, 



p. 322, 1834; Gosse, Actinologia Brit., p. 11, 1860. 

 Grihrina {pars) Elirenberg, op. cit., p. 40, 1834. 

 Metridium Edw. and H., CoralL, i, p. 252, 1857 ; Verrill, Mem. Boston Soc. Xat. 



Hist., i, p. 21, 1864. 



Column very changeable, in full expansion usually tall, pillai'-like, 

 expanding toward the disk, or lower and nearly as broad as high ; in 

 contraction forming a low cone ; surface nearly smooth, with abundant 

 mucus ; integument firm, thickened when old, forming at some distance 

 below the margin a thick smooth fold, above which the wall is thinner 

 and translucent. Disk broad, frilled, or thrown into lobes or broad 

 undulated folds, toward the margin. Tentacles very numerous, the 

 inner ones larger, more or less scattered on the disk, the outer ones 

 becoming gradually smaller and more crowded, those at the margin 

 very small and crowded. Walls perforated by scattered openings, 

 not very apparent excej^t when fully expanded. Acontia abundant, 

 but not often emitted except when greatly irritated. 



Metridium fimbriatum Veniii. 



Proceedings Essex Inst., vol. iv, p. 151, 1865. 



Base broadly expanded. Column very changeable, either low and 

 broad, or greatly elongated, the fold or " parapet " nearly an inch be- 

 low the margin. Tentacles very numerous, encroaching so much upon 

 the disk as to leave only a narrow central area around the mouth, 

 short, very slender, filiform, jjointed. Edge of disk thrown into nu- 

 merous deep frills. 



Color of column variable ; often translucent pale orange, punctate 

 with dark brown ; or light umber-brown ; tentacles a lighter tint of 

 the same, white within; mouth deep orange, or light yellowish brown, 

 surrounded by a broad baud or halo of purplish. 



Harbor of San Francisco, Cal., adiiering to the bottom of floating 

 piles, etc., Oct., 1855, — Dr. Wm. Stimpson ; Puget Sound, — Dr. C. B. 

 Kennerly. 



This species is closely allied to 31. marginattim of the New Eng. 

 land Coast, and 31. dlanthus of Europe. From the former it appears 

 to diflfer chiefly in having longer and more slender tentacles, with 

 the " parapet " farther from the margin of the disk. 



It is possible that the three will eventually be fouud to belong to 



