52 VERRILL, SYNOPSIS OF 



Actinoloba (pars') Blainv., Diet, dcs Sci. nat., 1830 ; Gosse, Actinolo- 

 gia Brit., p. 11, 1860. 



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



Metridium Edw. and Haime, Coralliaires, I, p. 252, 1857; Verrill, 

 Mem. Boston Soc. Nat. Hist., I, p. 21, 1864; Trans. Connecticut Acad- 

 emy, I, p. 478, Feb., 1869. 



Form very changeable, sometimes as broad as high, at 

 other times very much elongated, pillar-like, the disk 

 broader than the column and undulated or frilled at the 

 margin. Basal disk broad, well developed, highly mus- 

 cular. In contraction the form is usually that of a low 

 cone or hemisphere. Surface of column smooth, with a 

 distinct thickened fold near the top, above which the in- 

 tegument is thinner than below. Cinclidee scattered over 

 the sides, not very numerous, inconspicuous, without 

 raised borders. Acontia abundant, but not often emitted 

 except when much irritated. Tentacles small, very nu- 

 merous, scattered on the disk, the inner ones at a consid- 

 erable distance from the margin and much the largest; 

 the outer ones very small and crowded at the margin, 

 where they form a dense fringe. 



METRIDIUM FIMBRIATUM Verrill, these Proceedings, 

 Vol. IV, p, 151, 1865; Trans. Connecticut Acad., Vol. 

 I, p. 478, 1869. 



Harbor of San Francisco, Cal., adhering to the lower 

 surface of floating timber, October, 1855. Dr. William 

 Stimpson. Puget Sound. Dr. C. B. Kennerly. 



METRIDIUM sp. 



A species which has a well-marked submarginal fold, 

 but with the marginal tentacles larger than usual in the 

 genus. 



Port Jackson. Dr. "Wm. Stimpson. 



CEREUS Oken. 



Cereus Oken, Lehrbuch der Naturg., Vol. Ill, p. 349, 1815. (Type, 

 C. bellis.) 



Actinocereus Blainv., Diet. Sci. Nat., Vol. LX, p. 194, 1830. 



