FOSSIL At.CYON!A. 



41 



onia than even that of Count Marsilli, and was able to as- 

 certain by the aid of a magnifying glass, the peculiar 

 forms assumed by the spines of which these animals are in 

 a great measure composed. Of these we shall soon ha\e 

 occasion to speak more particularly. 



The forms in which these animals exist are very mime- Exist in var*. 

 rous; this depending not merely on the number of species, °us forms. 

 but on the different irregular forms which the same species 

 under different circumstances may assume. Thus Mar- 

 silli observes the same alcyonium, which sometimes grows 

 flat, and thus covers large pieces of rocks, is at other times 

 found in a rounded form. . 



From the different colours as well as forms which some Named from 



of the species of these substances possess, they have ob- t,ieir rese «- 



. . . blance to 



tained names expressive of their resemblance to certain fruits. 



fruits. Thus the alcyonium lyncurium, being of a globose 

 form, of a fibrous internal structure, of a tubercular sur- 

 face, and of a yellow colour, has been termed the sea- 

 orange : the a, bursa being of a sub-globose form, of a ' 

 pulpy substance, and of a green colour, has been termed 

 the green sea-orange or sea-apple : the a. cydonium, which 

 is of a roundish form, and of a yellow colour, has been 

 distinguished as the sea-quince: and the a.Jicus, from a 

 very close resemblance to the fig in its form, has been called 

 the sea-fig. 



The sponge is a fixed, flexible animal, very torpid, va- Characters of 

 rying in its figure, and composed either of recticulated sponge*, 

 fibres, or masses of small spiculae interwoven together, 

 which are clothed with a living gelatinous flesh, full of small 

 mouths or holes on its surface, by which it sucks in and 

 throws out the water. 



The vitality of sponges had been suspected by the an- Their animal 



cients, even in the time of Aristotle; they having; per- natur ® f"*". 



■ , ■ , , . . J ?„ J pected by the 



ceived a particular motion in their substance, as if from ancients, 



shrinking, when they tore them off the rocks. This opi- 

 nion of their possessing a degree of animal life was also en- 

 tertained in the time of Pliny. Count Marsilli * confirmed and conftrmej 

 $his opinion by observing, on their being taken out of the ^l (Qs ^ 



* Histoire Physique de la Mer. p. 53. 



sea, 



