770 



NEPTUNE'S CUP. 



smooth and regular as that of the Funnel-sponge, being mostly cut into notches and the 

 intervals developed into lobes. 



One remarkable characteristic of this species is the very brittle exterior, which can be 

 broken away by the ringers, and is found to consist almost wholly of flinty spicules, 

 cemented together by the glutinous substance of the animal. Sometimes it almost loses 

 the cup-like form, and spreads out like a fan, deriving therefrom the popular title of SEA- 

 FAN. As the term, however, is applied to many other marine beings, it is not thought so 

 useful as the name which has already been mentioned. 



OUR last example of the Halichondrife is seen investing the tipper part of a zoophyte. 



Many of these creatures, especially the sertularia and its kin, are very liable to the 

 gentle but irresistible attacks of this Sponge, which, settling upon them, increases rapidly 

 and more or less envelops them in its own mass. Its mode of growth is always variable. 

 Sometimes it follows all the branches of the zoophyte on which it is parasitic, causing it 

 to resemble a tree thickly covered with ivy : while at other times it spreads out so widely, 



NEPTUNE'S CUP. Tlialdssema 



that it'gathers all the branches together, covers them with its own substance, and forms 

 them into a shapeless spongy mass from which a few ends of the branches vaguely 



protrude. - , 



This Sponge does not, however, confine itself to zoophytes as resting-places, but seti 

 upon stones, sticks, shells, and other objects. Its colour is generally greyish white, but i 

 sometimes deepens its tint and becomes of a yellowish brown. The texture 

 substance is always rather coarse, but its softness differs greatly according to the object 

 on which it has established itself and the locality in which it happens to be. Ine s spic 

 are always short, rather curved, and are sharpened at one end and rounded at the c 

 About forty species of the genus Halichondria are found in our seas, several ot wlu 

 are remarkable for having the spiculse knobbed at both ends. 



THE extraordinary object which is called by the appropriate name of NEPTUNE'S CUP 

 is one of the most magnificent, as well as one of the most notable, of the Sponge 1 

 It hardlv looks like a Sponge; and. when a specimen is shown to persons who have 



