386 INTRODUCTION TO CONCHOLOGY. 



and well-being of these humble mollusks, — these headless 

 creatures^ blind also^ and incapable of motion. There is, 

 also, much of beauty in the internal arrangement of their 

 shells ; for these, in common with others that pertain to the 

 Brachiopoda, are distinguished by several interesting pecu- 

 liarities of stracture. When thin sections are examined by 

 the aid of a high magnifier, the effect is exquisite : it seems 

 as if the surface was raised with clusters of minute floral 

 leaves, resembhng those of the yellow everlasting, or globe 

 amaranthus. This result undoubtedly proceeds from the 

 effect of light and shade on the orifices of innumerable 

 perforations. 



A variety of appearances is presented also, according to 

 the interesting statement of Dr. Carpenter, to which we 

 have already referred, proceeding either from long flattened 

 cells, or plications in the cell-membrane, and readily dis- 

 coverable in even the minutest fragment. When also a 

 portion of one of the shells has been completely decalcified 

 by the action of dilute nitric acid, the membranous residuum 

 presents a very remarkable structure, of which no trace is 

 discoverable in ordinary bivalves. A series of tubular ap- 

 pendages are seen attached to the membranous films, 

 corresponding in diameter to the shelly perforations, and 



