igoy.] Records of the Indian Mt(scu)n. 65 



with a razor, so as to disturb the tissues as little as possible, it will 

 be found that the ectoderm is not closely folded as it is in a speci- 

 men preserved in spirit or even in one which has been killed in 

 formol and then dehydrated in alcohol and embedded in paraffin ; 

 but that there are large spaces between this layer and the meso- 

 derm, the two layers being only in contact at widely separated 

 points and there being a considerable amount of liquid enclosed 

 between them. The same condition, but not nearl3' to the same 

 extent, will be found to exist in young individuals of the new form, 

 while, except in the lower part of the column, it will not be de- 

 tected in full-grown examples of this form. In the neighbourhood 

 of the basal disk of these, however, it exists to a slight extent. In 

 specimens of the typical form which have been long in alcohol, as I 

 found in the types of the species, the ectoderm shrinks very greatly 

 (apparently more so than the mesoderm does) and therefore comes 

 to be nearly smooth again, lying parallel to the mesoderm. From 

 these considerations I conclude that there is naturally a layer of 

 water between the ectoderm and the mesoderm in the typical but 

 not in the new form of M. schillenanum — there are traces of it even in 

 the adult, and much more clearly in the young, of the latter — and 

 further that the folds of the ectoderm which are so striking a feature 

 of this layer in sections of the typical form (plate iii, figs. 5, 6) of 

 the species, are artificial. 



As to the function of this layer of water, which is confined to the 

 column : I would suggest that it is to enable the Actinian to endure 

 exposure to the sun out of water. The form is one which haunts 

 tidal waters and, as Stoliczka noted, has a great tendency to rnain- 

 tain its position near the surface and to return to that position if re- 

 moved from it. In the small cavities in which it is frequently fourid 

 ensconced, a certain amount of water remains when the object in 

 which they occur is left dry as a whole by the retreating tide.^ If 

 the animal is able to make use of this water by drawing t into 

 its body, as it may do by means of the cinclides, the habit of 

 living in such cavities must benefit it in more wa^^-s than one. My 

 reason for saying that it is possible that other species make use of 

 subectodermal spaces in the same way as the typical form of M . 

 schillerianuni is that I have observed in specimens both of this 

 form and of Sagartia troglodytes, Actinia mesembryanthemum and 

 other British species (especially when they are Hving under un- 

 natural conditions in foul water) that bUster-like projections 

 appear on the column, most commonly towards its base, and that 

 in the case of the Indian form these projections, which remain in 

 specimens preserved in formol, are due to accumulations of liquid 

 below the ectoderm. It is difficult to make observations as regards 

 the exact relation of one layer of the body to another on hving 

 materia^ , for the whole organism is so highly contractile that such 

 relations are distorted immediately on the application of a sharp 

 instrument to the external surface ; but water certainly exudes in 

 considerable quantities from the wall of the column of a living 

 example of the typical M. schillerianiim which is cut with a razor. 



