surrounding water where, after swimming about free for some time, it 

 finally settles down on some substance and loses its cilia, and 

 begins to lead a quiet immovable and undisturbed life on its own 

 account. 



Sponges vary greatly in form and size from a pin's head to 5 or 

 6ft. high. Some shapes are constant and characteristic, as the 

 fairy-like Venus Flower Basket, Euplectella, the glass-rope Sponge 

 with its cylindrical body, Hyalonema, the open Flower Basket 

 Sponge, Dactylocalyx and the Great Neptune's Drinking Cup, 

 Poterion ; but usually the shape is variable in the same species as 

 we have mentioned is the case with the Bath Sponge. 



The character of the skeleton is wonderfully diverse if we 

 consider the whole family of sponges, but in opposition to the 

 form, is tolerably constant in the same species, and it is therefore 

 taken as the basis for classification. Some sponges have no firm 

 skeleton ; they are mere jelly-fish amongst Sponges, and are called 

 Soft Sponges. In some, the skeleton consists of chalk spicules or 

 needles of different shapes. In some of flint spicules, and in some 

 of a network of horny fibres with no proper spicules. These then 

 are the four great divisions of Sponges. The different spicules are 

 beautiful objects for study with the Microscope. The members of 

 the clasd with flint spicules are the most numerous, diverse and 

 complicated. They are spread through all seas, at all depths, and 

 all ages, being found as fossils as early as the Cambrian system. 

 Amongst the species belonging to this class, is found the lovely 

 object whose skeleton is known as Venus, Flower Basket. 

 Euplectella, meaning a little thing beautifully woven. It has a 

 framework so exquisitely beautiful in its fairy-like tracery as to 

 have called forth the remark from a distinguished naturalist " this 

 passes the love of woman." Its spicules are so arranged crossing 

 one another as to weave together a thin walled vase of delicate, 

 very regular lattice work, with oblong meshes. The longitudinal 

 lines of the skelt^ton, and the transverse are remarkably regular, 

 the diagonal which are applied on the surface of the others, so that 

 they seem to stand out from them like delicate muslin folds, are so 

 arranged that every alternate mesh is left clear, whilst the others 

 are covered by them. At the base are an immense number of 

 silken glassy hairs, which envelope it almost completely. The lid 

 is of quite a different style of architecture, being an irregular 

 network of stout fibres, and containing none of the micros- 

 copic fibres that are so abundant in the body of the vase. 

 The lash chambers exist in the wall ; they are like cylinders, with 

 a large opening at one end, and perforated by pores, through which 

 the water is drawn by the lashes, a ad driven into the interior of 

 the vase, whence it escapes partly by the alternate open meshes in 



