and Physiology of the Sjwnyida. 5 



situated in the deep seas. None of these in such positions, 

 therefore, can be obtained by the dredge ; and it is only when 

 growing in such parts of the Laminarian zone that, as the tide 

 leaves them uncovered, they can be obtained by the hand, 

 unless gathered by divers from the rocks of the shallower seas, 

 who then restrict themselves to such species as are likely to 

 meet with a general and not a particular sale in commerce. 

 Those alone which grow on the ground can be scraped off by 

 the dredge or such like means ; and the rest, if not obtained 

 directly by the hand, come to us accidentally from the parts 

 where they grew. The latter are for the most part broken off 

 from their place of growth in deep water by having become 

 " heady," or too heavy to be held on by the root, or by violent 

 storms when growing on rocks in shallow water, after which, in 

 either instance, they may be carried about in the sea by currents 

 for a longer or shorter time, until they are finally thrown upon 

 the shore by the waves, wherein they become more or less 

 injured by trituration. After stranding on the beach they may 

 be picked up at once and preserved — or they may be drawn into 

 the sea again and again, and thus washed along the beach as 

 the wind changes, up and down, backwards and forwards, 

 buried and unburied in the sand and pebbles repeatedly, even 

 for years, until they come into the possession of the collector. 

 In the first instance more or less of the flesh or soft parts 

 may remain upon them ; but in the second, of course, nothing 

 will be left but the skeleton ; and in this state, for the most 

 part, they at last find their way into our museums, picked up, 

 perhaps, on some Survey by one 



u Who loves to roam aloiig the shore, 

 Where none have ever walked before." 



Hence it may be easily conceived that, such specimens 

 being analogous to a deciduous tree in winter, no further 

 description of them can be given than that which the bare 

 skeleton permits. Again, as it is in the deeper water (from 

 its stillness), and for the most part probably in submarine rock- 

 caverns, pendent from the roof or projecting from the sides, 

 that sponges attain their largest dimensions, so the larger 

 specimens in our museums may be assumed to have come 

 chiefly from these localities, and in the way and state above 

 mentioned. At the same time, it should be remembered that 

 there are several " land-locked " places where the sea is ever 

 more or less calm ; and therefore the same stillness which 

 exists at great depths, and is so favourable to large growth, 

 may be found in comparatively shallow water. 



Notwithstanding all this, the Laminarian zone of our coasts, 



