VIEWS OF THE MICROSCOPIC WORLD. 



of England. A profile of this shell, magnified twelve times, and bearing some 

 resemblance to a fan, is shown in figure 86. When a side view is taken, and the 

 fossil is highly magnified, the beauty of the structure becomes more apparent, and 

 the fluted projections, d d, are revealed as elegant spiral shells, divided into several 

 apartments, and presenting an appearance similar to that which is exhibited in 

 figure 87. 



The Textularia or entwined animal has the figure of a cluster of 

 globes, rising in the form of a pyramid, and when a section is made in 

 the direction of its length, it displays the different cells into which the 

 cavity of the shell is divided. In figure 88 is shown a specimen from 

 the marl of the Mount of Olives, and an outline of the American sextu- 

 laria is also exhibited in figure 89. This species differs in some respects 

 from other Textularia, being wholly local and peculiar to the chalk marls 

 of the Upper Missouri ; of which vast deposit it forms the prin- 

 cipal part. The living Xanthidia, or Cross-bar protophytes, 

 have already been described ; and in figures 90, 91, 92 and 93 

 are presented several specimens as they appear in flint. In this 

 stone they often occur in great abundance, no less than twenty 

 being once discovered by Mr. Hamlin Lee, in a chip of flint, the 

 surface of which was scarcely the twelfth of an inch in diameter. 

 These organisms are easily detected in flints which are translu- 

 cent; the only preparation required being simply to select the 

 thinnest and clearest flakes, struck off by the blow of a ham- 

 mer, and before viewing them with a microscope, to immerse 

 >them in oil of turpentine, in order to render them more trans- 

 parent. The specimens of Xanthidia represented in figures 90, 91, 92 and 93, were 

 taken from a remarkable group, described by Dr. Man tell, and found by his son in a 



Fig. 



Fig. 90. 



Fig. 91. 



Fig. 92. 



Fig. 93 



flake of flin*. This flake is delineated of its natural size in figure 90 ; in figure 91 

 it is considerably magnified, and the several fossils are distinctly seen. Figures 92 

 and 93 are two of the specimens very highly magnified, and are a variety of the 

 Branched Xanthidium, which is found only in a fossil state. That they belong t 



