480 Yerrill, N'otes on JRadiata. 



Cereus Oken. 



CereMS Oken, Lehrbueh der Naturg., iii, p. 349, 1815, (type, C. hellis). 



AcUnocereus Blainv., Diet. Sci. Nat., Ls, p. 194, 1830. 



Cribrina (pars) Ehr., Corall., rothen Meeres, p. 40, 1834. 



Sagartia {pars) Gosse, Trans. Linn. Soc, xxi, p. 274, 1855; (Scyphyia) Actinologia 



Brit., p. 25, (123), 1860. 

 Cereus (pars) Edw. and Haime, CoraU., i, p. 263, (269), 1857. 

 Cereus Verrill, Bulletin Mus. Comp. Zool., p. 58, 1864; Mem. Boston Soc. Nat. Hist., 



p. 24, 1864. 



Column verj^ changeable in form, capable of becoming tall, pillar- 

 like, or contracting to a low, depressed cone ; no submarginal fold ; 

 upper part with small, inconspicuous, contractile suckers ; walls nearly 

 smooth, pierced by scattered, inconspicuous pores or cinclidfe. Disk 

 broadly expanded, wider than the column, sometimes undulated at the 

 margin. Tentacles numerous, more or less scattered on the disk, usu- 

 ally rather stout, the inner ones considerably largest ; the outer ones 

 quite small. Type, 0. hellis. 



Oken, in constituting this genus, stated that the walls are per- 

 forated, and named C. bell'ts as a typical species, therefore it seems not 

 only proper, but necessary, to restrict the name to the group which 

 contains that species. Edwards and Hairae have erroneously extended 

 the genus so as to include all the imperforate, verrucose species, be- 

 longing to Urticina and Bunodes, as well as C. bellis and allied species. 



Cereus Fuegiensis Verriii. 



Actinia Fuegie isis Couthouy, op. cit., p. 145, Pi. 4, fig. 32, 1846. 



Discosoma f Fuegiensis Edw. and Haime, Corall., i, 257, PI. 02, fig. 2, (from Dana, 



Zooph.), 1857. 

 Sagartia Fuegie sis Gosse, Actin. Brit., p. 38, 1860. 



" Subcylindrical, 2 inches in diameter, exterior smooth, upper and 

 lower extremities sparingly dilated, margin of base slightly undulate ; 

 tentacles tliroughout remotely scattered, turgid, 3 lines long ; mouth 

 small, circular, 5-cleft ; form of animal when contracted very much 

 depressed, convex." 



The tentacles are scattered over a large part of the disk, about 1 

 to 1 "5 lines apart, nearly in five series, and have " the form of a grain 

 of wheat." The inner ones are consideral)ly largest. 



Disk bright orange ; column darker orange, with transverse paral- 

 lel lines or markings of dark brown ; tentacles grass-green ; mouth 

 pale orange. 



Orange Harbor, Terra del Fuego, on rocks, — J. P. Couthouy, U. S. 

 Expl. Exp. 



