MICROSCOPE AT THE SEA-SIDE. 71 



Cliona, found in the shells of old oysters, which 

 has its spicules pin-shaped, as seen at figure 142. 

 The fresh-water sponge has very peculiar-shaped 

 spicula, and is represented at figure 143. In some 

 the siliceous bodies are round, with projections, 

 as in Tetliea, seen in the drawing, figure 145. 

 Sometimes the spicula assume a stellate form, 

 and are even branched, as in the spicula of an 

 unknown sponge given at figure 144. 



Amongst the lowest forms of animal life, none 

 are more interesting to the microscopic observer 

 than those belonging to the family of Foramini- 

 fera (Hole-bearers). They are thus called on 

 account of the minute holes which cover their 

 shells. If we suppose a creature as simple in 

 structure as the amoeba, or sun animalcule, of which 

 we have previously spoken, and which are figured 

 in 16 and 17, plate 1, with the power of forming 

 a little calcareous shell, we should have a foramini- 

 fer. Some of these shells have the form of a 

 nautilus, and when first observed they were sup- 

 posed to belong to this group of shell-fishes. In 

 form they certainly resemble the higher forms of 

 mollusca, as may be observed in figures 21 and 24, 

 in plate 1. Sometimes, however, they are elon- 

 gated or cone-shaped, as in figure 25. Other forms 

 are seen in figures 20 and 22. They may often 

 be found alive -at the sea-side, nestling in the roots 

 of the gfgantic tayles which are so often thrown 

 on the shore after a storm. If the roots of these 

 plants (Laminarice) are washed, and the deposit 

 examined carefully, the foraniinifera will be seen 

 at the bottom of the vessel, and may be picked 

 out one by one. When this is done, they will be 

 found to have the power of protruding through the 

 little holes in their shells their soft bodies, in the 

 form of long tentacles, as seen at figure 24, in the 



