2*20 FUNCTIONS AND INSTINCTS. 



the class of Tunicaries are interesting on account 

 of their singularity and beauty, I shall only select 

 two, one from the aggregated, and one from those 

 that are simple, for description and further re- 

 marks, and then proceed to the great class of 

 Molluscans. Who would think, asks Lamarck, 

 that the Pyrosome, first observed by Peron and 

 Le Sueur, was an assemblage of little aggregate 

 animals ; any one that looked at this animal, or 

 at Savigny's figure of it, 1 would mistake it for 

 a simple polype, with a number of leaf-like ap- 

 pendages growing from its skin : but a closer 

 examination would give him a very different 

 idea, and he would discover, with wonder, that it 

 was a mass filled with animals, united by their 

 base, exceeding the number of the above append- 

 ages. The common body that contains these 

 creatures resembles a hollow cylinder closed at 

 its upper extremity and open at the lower ; this 

 body or mass is gelatinous and transparent, a 

 number of tubercles of a firmer substance than 

 the tube, but at the same time transparent, po- 

 lished, and shining, differing in size, cover the sur- 

 face ; some being very short, and others longer, 

 and the longer ones terminated by a lance-shaped 

 leaflet. At the summit of each tubercle is a cir- 

 cular aperture, without tentacles, opposite to which 

 is another circular orifice which is toothed. 

 The pyrosomes are the largest of the phosphoric 



1 Anim. sans. Verttbr. PL. IV. FIG. 7. 



