44 ECHINODERMATA. 



cat among quadrupeds. More of the tenants of the same waters are per- 

 haps rather under it than above it. Thus, such creatures must have suffi- 

 cient subsistence, of whatever kind it may be, and however obtained. 



A learned author indeed, already quoted, the Professor Delle Chiaie, 

 to whose minute anatomy of the Holothuria science is deeply indebted, 

 seems to conclude, that the ah'ment of these animals is chiefly vegetable 

 and miscellaneous subtances, in saying, " Le Oloturie cibansi di figli, di 

 coralline, di alghe, di arena e di altre immondezze di mare."* But such 

 would be rather indigestible ingredients, whence it is not improbable that 

 heterogeneous matter of the kind, instead of being the subject of choice, 

 may be intermingled with or adhering to animal substances, and swallowed 

 along with them : Nor is so great an exception to general rules admis- 

 sible without farther evidence. No naturalists of my acquaintance, 

 among the few having had opportunities of dissecting this animal, found 

 any definite remains in its intestines ; and whatever I may have myself 

 observed, might be rather referred to the residue of substances purely 

 animal, than to vegetable or zoophytical products. 



The food of the Holothuria seems still problematical. 

 Nevertheless, the tentacular evolutions are too remarkable too pe- 

 culiar a feature and altogether unexampled, in as far as I know, among 

 living beings, not to excite great curiosity regarding their specific pur- 

 poses. The incurvature of these organs ensues alternately, not succes- 

 sively, in regular order following the first in action : but the same ten- 

 taculum is never observed to descend twice into the orifice of the mouth ; 

 one or two of the circular series always intervenes. However, one of the 

 antennulae uniformly descends after a tentaculum is down, and the other 

 frequently replaces this tentaculum when withdrawn. Sometimes both 

 antennulae remain a short time below, after the tentaculum has returned : 

 and their office there evidently occupies them much longer than that 

 of the tentaculum, which always rises speedily to resume its full dimen- 

 sions from the contracted state. With this alternate or successive exer- 

 cise the animal continues engaged whole hours, after a manner both to 

 the entertainment and admiration of the spectator. 



* Delle Chiaie, Descrizione Zoologica ed Anatomica de Alcuni Specie di Oloturia, 8. 



