ANEMONES 



385 



in shape. In its greater diameter lies the elongate mouth, with prom- 

 inent lips, and a single siphonoglyph. 



The oral disk and tentacles are smooth. The column, though ex- 

 hibiting in contraction numerous strong transverse wrinkles and slight 

 incidental roughenings, is smooth in expansion, with twenty-four 

 shallow longitudinal furrows indicating the bases of the mesenteries 

 (PI. XXIV, fig. 4). Between every two adjoining mesenteries in the 

 upper portion of the column is a row of cinclides. These are quite 

 regularly spaced, one in every row lying approximately in the cross 

 section of the column. As there are twenty-four rows in all, the cin- 

 clides of one row open into exocoels, those of the next into endocoels. 



The color of the column is a dirty white. The tentacles are pale 

 green, marked with three or four grayish-white bands and a longitudi- 

 nal row of fine white milky dots on each side. 



Structure. — The ectoderm of the body wall is composed of high 

 columnar epithelium, in which nematocysts and gland cells with 

 granular contents are abundant, and goblet cells not uncommon. The 

 mesogloea is thick, with conspicuous lamellae. The parietal endoderm 

 is low, with few gland cells. 



D OL m D 1 H tf 



Fig. 16. Harenactis aiienuaia. Diagram showing symmetrical arrangement of 



mesenteries and their structure with respect to the siphonoglyph. 



The oral disk is furnished with ectodermic muscles which are con- 

 tinuous with the longitudinal muscles of the tentacles. The tentacles 



