44 Anatomy of Sagartia Schilleriana [No. 1, 



of the animal is not known, and various suggestions have been 

 made as to their signification. It appears to me that most pro- 

 bably they represent some organs of secretion. It is, however, 

 likely that they also serve other purposes at the same time. I 

 shall subsequently relate a case which tends to prove that they 

 are especially active when the Sagartia takes some food into its 

 stomach, thus, by their natural central position, they not only guard 

 the reproductive organs against any injury from hard particles which 

 are received as food into the internal cavity, but they most probably 

 also facilitate the maceration and digestion of the food. The ready 

 nutriment, or chilus, must be absorbed by the entire inner surface of 

 the body, for no special organs are observable for its distribution. 



1. Next in importance, for the existence of the animal, appear to be 

 the acontia, which are also flat bands consisting of cnidce ; these being 

 likewise arranged transversally in two rows on either side, leaving a 

 narrow space in the centre which is, however, in the present case occu- 

 pied by large transparent cells, a very small quantity of a fine granular 

 substance, and by cnidce of different size (see figs. 9, 9a, 9b, pi. XI). 

 The marginal cnidce are projecting at the edges about one-fourth or 

 one-fifth of their length, and not unusually have their ecthorcea ejected. 

 The cnidce of the acontia are distinguished by their great length 

 (some of them being above y^oth of an inch) ; they are either straight, 

 or more often slightly curved, and almost equally attenuated on both 

 ends. The ecthorcea, when ejected, often exceed the cnidce by one 

 half of their length, and are sometimes doubly as long ; their thickness 

 is about y-g-th of that of the cnidce, being hollow and provided nearly to 

 the tip with short, reversed cilia (fig. 9a, pi. XI). It is not improba- 

 ble that the ecthorcea of all the other kind of cnidce are also bearded 

 but I have not been able to observe their minute cilia. The 

 cellular substance in the centre of the acontia is transparent, but 

 the large number of the marginal cnidce produces a milky white 

 colour, which strongly contrasts with the purple colour of the ovaria 

 and the yellowish craspeda, and thus_ makes the acontia readily 

 discernible. 



The acontia are in constant motion, expanding and contracting 

 and winding up and down in different directions ; their movements 

 being much quicker, than those of the craspeda. Their length 



