Nervous System of Actinia. 271 



granules, and granular cells, which merge gradually into the close layers 

 of granular cells under the Eotteken bodies, and they transgress here 

 and there on those layers. 



The fusiform cells are numerous (PL II. figs. 18-24), and may be di- 

 vided into two kinds : (a) Those with irregular shapes and short ter- 

 minal processes, which are prolongations of the cell-wall and are rounded 

 off. These cells contain either highly refractile nuclei, or several nuclei 

 with granular nucleoli. The fusiform shape is not invariable, and in 

 Plate II. fig. 20 a large cell twice the diameter of a Eotteken body 

 is seen amidst the granular plasm. It has a tail-shaped prolongation and 

 some highly refractile nuclei. 



/3. Those which are rounder in outline, and whose projections are long 

 and continuous with those of others. The outlines of these cells are 

 soft, and without definite and sharp margins, and the, colour is a very 

 pale blue-grey. They contain one or more very distinct nuclei. Our 

 type, illustrated in Plate II. fig. 21, has its cells rather wider than 

 a Eotteken body, and they are connected by a process with sharply 

 defined wells the cell, with many nuclei, having a long caudal fibril of 

 a pale grey colour and rather sharp marginal lines which had suffered 

 disruption. 



A second type has large spherical or elliptical cells, which do not have 

 processes passing out in opposite directions, but they are restricted to 

 one part. Usually the cells have only one process, but sometimes two 

 exist close together (fig. 22).. 



These cells are granular within and have very indistinct nuclei ; the 

 cell-wall is extremely delicate, and the whole is of a pale grey colour. 

 The fibrils of these cells are particularly connected with the plexiform 

 tissue. In Plate II. fig. 22 there is a cell with two fibrils one is 

 short, for it dips down and is foreshortened, and the other is very long ; it 

 bifurcates, and one end joins a rounded mass of the plexus, and the other 

 the rugged fibrillar part. 



In Plate II. fig. 24 a cell with one fibril is shown. The fibril swells 

 slightly, and then passes down to join a transverse fibre belonging to the 

 plexus. 



The plexiform tissue is probably continuous around the Actinia beneath 

 the chromatophores, for it is found between the circular band of mus- 

 cular fibres and every chromatophore. It consists of an irregular main 

 structure and of lateral prolongations, which either anastomose with the 

 fibrils from the fusiform and more spherical cells, or are directly con- 

 tinuous with the cells (fig. 23). 



The main structure resembles, in its indistinctness of outline and its 

 pale grey colour and indefinite marginal arrangement, the fibre of the 

 sympathetic of mammals, but it is less coherent and smaller. The 

 usual appearance (Plate II. fig. 23) is that of a grey film with definite 

 branches, and the whole has few granules here and there and a very few 



