INTRODUCTION. 
Intestina, simple, naked, destitute of limbs. 
Mollusca, simple, naked ; but not without limbs. 
Testacea, animal with a calcareous covering. 
Lithophyta, animal composite, affixed to, and fabricate a calcareous 
base.—Coral. 
Soophyta, a vegetating stem like a plant ; animal composite, and . 
resemble flowers. 
Linnzus has included in the Testacea Order the whole tribe of 
Shells. In the generic characters he regards both the Shell and its 
inhabitant: in the definition of species, the former only is attended 
to. There are very strong arguments against the method of arrang- 
ing this tribe by the Animals, although it cannot be denied, that the 
Shells are only the coverings or habitations, and should not demand 
our primary attention *. - 
The TEesTAcEA are Vermes of the soft and simple kind, and are 
covered with a calcareous habitation. ‘These are separated into three 
divisions, according to the number of valves of which the Shell con- 
sists. ‘The first division includes only three genera, Chiton, Lepas, 
and Pholas; these are called Multivalves, and are formed of many 
valves, or pieces, disposed transversely on each other. The second 
division consists of Bivalves, or Shells of two pieces, connected toge- 
ther with a hinge, or cartilage. ‘The third division is of Univalves, 
and have the Shell complete in one piece, as the word implies. The 
Linnzan genera are— 
* Vide Donovan’s Instructions for collecting and preserving Subjects of Natural 
History. London, 1794. 
