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 fingers, 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 Halichondriae is seen investing the upper 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 CVP.-Thalasscma Neptuol. 



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 

 settles upon stones, sticks, shells, and other objects. Its color is generally grayish 

 white, but it sometimes deepens its tint and becomes of a yellowish brown. The tex- 

 ture of its 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. The spiculae are always short, rather curved, and are sharpened at one end and 

 rounded at the other. About forty species of the genus Halichondria are found in our 

 seas, several of which are remarkable for having the spicuke 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 tribe. 

 It hardly looks like a Sponge ; and when a specimen is shown to persons who have no 



