28 ECHINODERMATA. 



fice, the animal survived under it four or five days : Plate II., fig. 5. 

 Outline of the body a, a, a, a, suckers b, h, b, b, orifice c, respiratory or- 

 gans protruding d. 



These organs are obviously distended by reception of a fluid, which 

 may be presumed the sea-water, amidst which the Holothuria dwells. 

 But the mode of their replenishment, by what channels or absorbents, is 

 by no means evident. Perhaps it is by alternate discharge and replenish- 

 ment that the respiratory functions, those so essential towards life and 

 salubrity, are effected. If, in passing from the tubes, there is an accu- 

 mulation m the great cloaca or reservoir, the powerful muscular contrac- 

 tion of this organ may produce a continued jet. But while this goes on 

 it is rational to conclude that imbibition or absorption by some other 

 organic structure contributes the supply. 



The whole is a very admirable and extraordinary apparatus, con- 

 sisting of such a multitude of subordinate parts, that it is impossible to 

 represent above two-thirds of them. 



The opinions of naturalists do not correspond regarding an impor- 

 tant portion of the animal fx-ame, the nervous system. 



DeUe Chiaie, who seems to have had tenfold the number of speci- 

 mens of any other observer, says the Holothuria has no nervous system, 

 since the most diligent investigation could not discover any traces of it — 

 " that no one could be more favourably situated than himself, with 

 thousands of living Holothuri^e, whereon he was occupied constantly 

 during ten months in dissection." * 



Professor Goodsir, of the University of Edinburgh, no less a dis- 

 tinguished anatomist, acquaints me, that he ascertained the nervous 

 system of the Holothuria to he in a pentagonal form around the ten- 

 tacula, descending the body in five cords, so as to be connected with the 

 rows of pedicles or suckers. 



Tlie preceding author, Delle Chiaie, enters on some explanation of 

 the sanguiferous system. 



He also speaks of the animal feeding on fragments of algge and the 



* Delle Chiaie, Memorie sulla Storia e Notomia degli animali senza Vertebre, vol. i. 

 p. 100. 



