On the Nervous System of Actinia. 73 



and filiform (PI. LXIX., Figs. 9-14). The filiform arrangement 

 of the granulo-cellular protoplasm is often branched, and a set of 

 elongated masses may unite ab(3ve or below the bodies. The cells of 

 this intermediate tissue are small and usually spherical ; in one kind 

 there is a large refractile nucleus, but in the commonest varieties 

 the cells simply contain granules. It is necessary to study this 

 tissue, because of its close agreement to what I presume to be the 

 nerve structure, in some, but not in the essential, points. This 

 tissue is clearly continuous with that which has already been 

 noticed as separating and bounding the larger refractile cells outside 

 the Eotteken bodies, and it is continued amongst the small closely- 

 set granular cells which underhe these interesting histological 

 elements (PI. LXIX., Fig. 13). 



The intermediate tissue binds together the bacilli, for it is con- 

 tinued upwards and between them, the large refractile cells (which 

 I propose to term " Haimean bodies "), and the " Ptotteken bodies," 

 and it becomes lost in the cells upon which the proximal ends of 

 these last rest. 



It contains the granular structures which give, in the mass, the 

 colour to the chromatoj)hore, and it is evident that the Haimean 

 bodies are developed from it. 



The proximal ends of the Eotteken bodies retain their sharp 

 and rounded contour amidst the dense layers of small granular cells 

 which everywhere underlie them. 



Those granular cells form a tissue through which light passes 

 with difficulty under the microscope. They are regularly placed 

 in series near the Eotteken bodies ; but deeper they become less so, 

 and then other anatomical elements may be observed between them 

 and the muscular fibres upon which the whole cliromatophore 

 rests, and which in their turn limit externally the endothelium. 



III. A Notice of Bottehens discovery of Fusiform Cells and of the 



different ajjpearances of the Nervous Elements noiv first 

 observed in the " Plexiform Tissued 



Eotteken describes these nervous elements as extremely fine 

 fibres and spindle-shaped cells, and asserts that they are probably 

 nerve fibres and cells. But he has not traced them in conjunc- 

 tion, nor have the fibres been seen of sufficient length to anasto- 

 mose. 



I have found the fusiform bodies and their long ends — the fine 

 fibres mentioned above. Moreover the connection of these irregular- 

 shaped cells has been determined in these investigations, and the 

 anastomosis of their processes and their connection with parts of a 

 plexiform nervous tissue also. 



These structures are in the midst of a mass of viscous proto- 



