124 EXCESSIVE IRRITABILITY. 



far the best for the Aquarium, where, with a little care, it will 

 continue to thrive for years and occasionally present its owner 

 with a family of little ones. The common Sea-cucumber (Cu- 

 cumaria communis) is another of our smaller species well 

 adapted for confinement ; although, living for the most part below 

 the tide marks, it is not so easily obtained. It is curious to 

 observe the movements of these animals in the Aquarium, loco- 

 motion being effected partly by means of the tubular sucker- feet, 

 and partly also by the alternate extension and contraction of 

 the body, as in the case of the common earth-worm and its 

 allies. 



This worm-like mode of progression is characteristic of the 

 Holothurice, and shows, more clearly than anything else, the 

 nearness of their approach to the Articulate animals, which stand 

 next above them in the scale of creation. It is mainly owing to 

 the highly contractile nature of their muscular system, which is 

 so strongly developed and complicated as to enable these animals to 

 alter their form and appearance in the most remarkable manner 

 at pleasure. Thus, while the great Sea-cucumber already men- 

 tioned is only about a foot long in a state of rest, it can quickly 

 elongate itself to a length of nearly three feet, and then, it may 

 be, suddenly contracting, it will puff itself out in the form of 

 a globe, when, taking another whim, it nips itself in at the mid- 

 dle, and quickly becomes an animated hour-glass ! Let no 

 humane observer attempt, however, to provoke a display of this 

 singular propensity ; for your Holothuria far from being " as 

 cool as a cucumber" is hot and irritable to an extraordinary 

 degree, and not unfrequently, on the slightest alarm or provoca- 

 tion, will throw itself into such violent contortions as to burst 

 asunder and discharge the whole of its viscera. " But," face- 

 tiously remarks Professor Rymer Jones, " the most wonderful 

 part of the tale is, that the catastrophe, so grievous to the 

 spectator who witnesses such a tragedy, seems to be of very 

 small importance to the actor, as the creatures seem to get on 

 just as well without any bowels as when possessed of such trifling 

 additions to their economy ; and, what is more, can reproduce 

 them in a most convenient manner, so as again to become furnished 

 with a complete set." 



It has already been hinted, that the Sea-cucumbers are used in 

 some parts as an article of food. In China they rank as great 



