The Actiniae of the Plate Collection. 285 



speciraens thej' were distinctly visible extending in loiigitudinal rows 

 from the marg-in almost to the limbus. Notwithstanding- their 

 presence no foreign bodies were adherent to the surface. 



In most of the individuals the margin was separated from the 

 bases of the tentacles by a distinct fosse, but in some this condition 

 was not so evident, although in such cases there could be disting- 

 uished immediately below the bases of the tentacles an area diflfering 

 from the rest of the column in lacking the reticular appearance and 

 in being- ridged longitudinally ; this area evidently represents the 

 fosse. No acrorhagi occurred. 



The tentacles were more or less exposed in all the specimens, 

 with one exception, in which the column had contracted to a low 

 dorne and the tentacles were completely concealed. Usually the 

 tentacles were only partially visible, that is to say, only the outer 

 cycles could be seen, the inner cycles being inverted and concealed, 

 but in two individuals all the cycles were visible and the tentacles 

 were seen to be thin-walled, smooth. flaccid structures equalling the 

 column in length ; their number was somewhat less than one hundred. 

 The disc and mouth were concealed in all the specimens. 



In the larger individuals the height of the column was about 

 1.3 cm, the diameter of the base 2 cm and the diameter at the 

 margin 0.9 cm. In the Single completely contracted specimen the 

 height was only 0.7 cm and the base measured 2 cm in one diameter 

 and 0.5 cm in the other. The tentacles, when most perfectly 

 expanded measured about 1 cm in length. The label accompanying 

 the specimens describes them briefly as "small green Actinians". In 

 the preserved condition they possess a uniform pale olive green 

 color. 



Structure. The mesogloea of the column wall averages about 

 the same thickness as the ectoderm, but it is raised on its outer 

 surface into numerous irregularly arranged ridges, which give rise 

 to the reticulate appearance of the column. The ectoderm contains 

 numerous gland cells, but at frequent intervals areas occur, sometimes 

 on the edges of the mesogloeal ridges and sometimes between the 

 ridges, in which the gland cells are wanting, the ectoderm consisting 

 of the long slender cells usually found in Verrucae and of "pyriform" 

 cells situated close to the mesogloeal surface. There is no doubt 

 that these areas are Verrucae. The circular muscles of the column 

 wall were moderately developed and a strong endodermal sphincter 

 (Fig. 76) occurred on the inner wall of the fosse. It consists in its 



