1909] Torrey-Kleeberger : Threi Species of Cerianthus. 117 



are banded with numerous broad stripes of delicate brown, the 

 ground being a faint pink or colorless. In about twenty per cent. 

 of the individuals, two tentacles, symmetrically placed, on either 

 side of the median plane, but not quite diametrically opposed, 

 are banded or solidly colored in a conspicuous manner with deep 

 red brown. The inner or labial tentacles, agreeing in number 

 with the outer, are but faintly tinted and without bands. 



In full extension, the column may exceed 20 cm. in length, w ith 

 an average diameter of something less than 1 em. Thus it is 

 about the size of ('. lloydi," but differs from the latter in the 



tstantly smaller number of tentacles, as well as in coloration. 



The column is thickly streaked and mottled with reddish brown. 

 Lightening orally. At the bases of the outer tentacles are deli- 

 cate markings in red brown. 



The column, thin walled, is highly contractile, as are also the 

 tentacles. The marginals may, in fact, be reduced to nothing, 

 may disappear completely on the way from the collecting ground 

 to the laboratory, and only gradually reappear and resume their 

 aormal size after many hours in aquaria. Such occurrences imi- 

 tate closely the more obvious facts of loss and restoration by 

 regenerative processes. Yet the disappearance and reappearance 

 are to be explained otherwise, namely, by variation in the internal 

 pressure of the water in the hollow tentacles and coelenteron. 3 ' 



There is little to be said of the sheath with which the animal 

 readily surrounds itself. It serves as a lining for the burrow, 

 is composed of a feltwork of nematocysts and is easily torn. 



Aborally, the body wall is pierced by a terminal pore. 



The long oesophagus is characterized by an unusually broad 

 siphonoglyph. The latter, indicated by the oblique shading in 

 fig. 1, does not reach the lips of the mouth, and extends into the 

 middle third of the column in contracted individuals, in connec- 

 tion with a triangular prolongation of the oesophagus. Opposite 

 the siphonoglyph is a very narrow and faint depression in the 



"See Gosse: The British Sea Anemones, 1680; also Andres: Fauna unci 

 Flora des (iolrVs von Neapel. IX. Die Aetinien. 



i^For the role of this internal pressure in the regeneration of tentacles, 

 see a series of papers by Child, in the Biological Bulletin from October, 

 1903, to April, 1905. See also the same author for an experimental study 

 on C. aestuari, in the Biological Bulletin for June, 1908. 



