452 THE AQUARIAN NATURALIST. 



though not, as it would seem, from seizing the bait. 

 The animal is round, from four to four and a half 

 inches in length, and of a reddish-brown colour, the 

 interior of the orifice being scarlet. Whether the 

 posterior extremity is sunk amidst the sand in its 

 natural state, and the other end disengaged above, 

 has not been ascertained. In captivity it always lies 

 horizontally, without any effort either to penetrate 

 downwards, or to shift its position. 



The ASCIDIA INTESTINALIS (PL VIII. fig. 5) bears 

 some resemblance to a Florence oil-flask, with two 

 necks of nearly equal dimensions, and is occasionally 

 met with three or four inches in length ; its appear- 

 ance is translucent, soft, and delicate. The ordinary 

 habitation of this species is between the valves of old 

 oyster-shells, wherein a group of five or six may some- 

 times be discovered closely packed together. But by 

 rending such double shells asunder, the Ascidiae are 

 often much injured ; for they are generally firmly 

 adherent by a large portion of their sides to both 

 valves, instead of being fixed by the base, as is gene- 

 rally the case in other species. Laceration or abrasion 

 is always fatal to the Ascidian. 



The young are nearly transparent, and consequently 

 well adapted for microscopic observation. Almost 

 the whole alimentary canal is frequently visible, 

 occupied by the muddy mass from which subsistence 

 is eliminated. 



