30 ECHINODERMATA. 



heat appear to be extremely prejudicial. Their safety depends on cool- 

 ness ; and, I firmly believe, that one principal difficulty opposing their 

 conservation is lodging them in too high a temperature. The specimen, 

 Plate I., survived five or six weeks. None other in the lapse of nearly 

 thirty years afforded a display of the tentacula equally luxuriant for de- 

 lineation. The Holothuria being properly a nocturnal animal, I was in- 

 debted for this to Mr Daniel TVTiyte M'CuUoch, an excellent artist, whose 

 labours generally commenced about midnight, when his subject had 

 reached its finest condition. 



The animals of this species are not nearly as stationary as those of 

 the following, which frequently remain for months in the same spot. 

 The small specimen, Plate II., fig. 2, was very active. It traversed its 

 vessel freely, and curved itself in all directions while quitting a wide 

 mouthed phial ; also advancing with the tentacula in front. But others 

 have been stationary in comparison, remaining affixed to the side of a 

 vessel for a considerable time, just at the surface of the water, and tes- 

 tif_ying little inclination to move. 



Among the numerous obstacles obstructing all observers, and which 

 have much retarded our knowledge of this curious creature, is its ex- 

 treme tendency to rupture. Such an accident, whether external or in- 

 ternal, is particularly incident to larger specimens ; and, as already 

 noticed, slight abrasion of the skin seems to be irremediably fatal. 



It does not appear that the rupture is confined to any part of the 

 hodj, though frequently ensuing in the vicinity of the terminal orifice of 

 the great cloaca. A prolapsus then follows, whereby the intestinal organs 

 are discharged in large proportion. 



Its progress and effects may be seen at the protrusion of part of the 

 respiratory tree, Plate II., fig. 5 ; also in the escape of some of the in- 

 testinal canal a ; the same organs, fig. 7, h ; and of an immature ovarium 

 among other organs, fig 8. 



Sometimes the rupture is in the side of the animal, not far from the 

 middle, when portions of the ovarium, almost mature, escape. An in- 

 testinal protrusion also sometimes ensues by the mouth, with rupture of 

 the body. 



