162 POPULAR HISTOPvY OF THE AQUARIUM. 



" The worm having been kept in sea-water unchanged 

 for two or three clays^ sickened, and by tlie more frequent 

 involutions and evolutions of the oral end evinced its unea- 

 siness. Being left unobserved in this state for an hour or 

 so, I found on my return that it had vomited U23 its ten- 

 tacula, its oral apparatus, its intestinal tube entire, and a 

 large number of ovaries which lay about the plate. The 

 muscular convulsion must have been very great to have thus 

 so completely embowelled the creature; and yet life was 

 not extinct, for the tentacula contracted themselves on be- 

 ing touched, and the empty skin appeared by its motions to 

 have lost little of its irritability.^^ 



A great deal of water circulates through these animals, 

 Dr. Johnston thinking that it is first forced through the 

 tubes of the feet, or suckers. The accumulation of water 

 in different parts of the body at different times causes those 

 parts to swell so as to change the form in the manner de- 

 scribed. 



Plate X. represents Mr. Lloyd^s self-mutilated Pentada 

 pentactes in the horizontal position at the edge of the water, 

 in which it has remained. The two lower specimens are 

 from the same collection; they are in health, of a white 

 colour, with tentacles orange and black. 



