42 ECHINODERMATA. 



The nature of the food, however, without ocular demonstration, 

 can only give birth to infinite conjectures. We cannot forget the ex- 

 treme timidity of the animal, which seems entirely to exclude living 

 prey. Likewise, the extreme delicacy of the tentacula apparently adapted 

 for entrapping only the smallest and weakest creatures, if that be the 

 mode of capture the most defenceless and least resisting, presuming the 

 Holothuria to be carnivorous, of which there is no evidence. By a com- 

 mon law, with few exceptions, the vast preponderance of aquatic animals 

 become each other's prey. The stronger overpower the weaker ; the 

 boldest fall the victims of artifice. So few are sustained on vegetable 

 products exclusively, that all may be said to perish as alternate sacrifices. 

 Many are devoured alive by enemies of such contemptible appearance, 

 as to form but specks in relative dimensions ; and some, though not 

 courageous enough to attack the living, feed greedily on the dead. By 

 the immutable ordinances of nature, incessant deperdition and incessant 

 reproduction prevail, whether on the earth, or amidst the waters. 



But how can the Holothuria be an animal of prey ? The presence 

 of a trifling insect seems to fill it with alarm, restraining evolution 

 of its arborescent organs ; and the contact of any extraneous, though 

 diminutive substance, commonly leads to their entire retraction from 

 view. 



Neither experiment nor observation regarding the food of the Holo- 

 thuria has proved satisfactory. The intestine is always full of a soft 

 brown or yellowish matter, and dark pellets are sometimes found in its 

 vessel, but under great irregularities in everything. 



Amidst infinite trials to preserve the life and vigour of different 

 specimens, I cannot affirm that any substance whatever has been accep- 

 table. Many particles of animal and vegetable matter were occasionally 

 brought in contact, or within reach, of the arborescent tentacula, which, 

 having rather an adhesive than a prehensile faculty, might convey them 

 towards the mouth. Likewise, when the weather was genial, and the 

 whole funnel finely displayed, I have dropped some fragments of mussel 

 gently on the tentacula. Their contact apparently excited a slight effort 

 in these organs to seize and convey them to the orifice of the mouth ; 



