Dixon — On Sagartia venusta and Sagartia nivea. 123 



and Halcampa, neither of which possesses acontia, points to the same 

 conclusion. Professor R. Hertwig definitely attributes the func- 

 tion of allowing water to pass in and out to the openings in 

 Halcampa clavus (Report on the Actiniaria, p. 97) ; but, so far as 

 I can discover, he does not identify these openings with the 

 cinclides. 



The white spots on the upper portion of the column in Sagartia 

 win iata, S. nivea, and S. venusta, are undoubtedly suckers. I have 

 seen a specimen of 8. nivea relinquish its hold with its base, and, 

 while fully expanded, attach itself to the glass side of the tank by 

 means of three of these spots ; subsequently it contracted, and 

 remained hanging by the three suckers for a considerable time. 

 The weight of the animal thereupon drew the suckers up into 

 sharply-raised and finely-pointed conical papillae. I have seen 

 Peachia adhere to the glass in a precisely similar way by conical 

 papillae, which were raised just close under the tentacles; but when 

 Peachia has relinquished its hold, the portion by which it held is 

 externally not distinguishable, to the eye at least, from the rest of 

 the body- wall. In Sagartia miniata, S. nivea, and S. venusta, how- 

 ever, the white spots on the column are the only portions of the 

 body which I have observed exercising this power of adherence. 

 The suckers are scattered irregularly all over the surface of the 

 upper third of the column, being of less size the more nearly they 

 approach to the margin of the disk. 1 They are not, like the cin- 

 clides, confined to the spaces between the lines made on the body 

 wall by the insertion of the mesenteries, but may be situated imme- 

 diately over these lines as well as in the spaces between them. This 

 account of the suckers I have given at the risk of stating again 

 something that is already well known. I have been induced to do 

 so by reading in Professor R. Hertwig's Report on the Actiniaria, 

 &c, p. 16, the following two rather concise sentences : " I have 

 entirely omitted the sucking papilla? in the general description of 

 the anatomy of the Actiniae, even in forms which are capable of 

 incrusting themselves with foreign bodies. I am the more justified 



1 Milne-Edwards (Histoire Naturelle des Coralliaires, 1857, vol. i., p. 272) places 

 Cereus (= Sagartia) venusta, under a group, in which " les tubercles verruciformes 

 occupant seulement la region inferieure des parois laterales du corps." But there is no 

 doubt the suckers are in all our Irish specimens much more conspicuous, at least, on 

 the upper portion of the column. 



