CRUSTACEA. 779 



deration. The English sailors and soldiers, who were obliged to walk in those 

 countries through marshy grounds, talked with terror of the number of leecnes 

 that infested them on their march. Even in some parts of Europe, they 

 increase so as to become formidable. Sedelius, a German physician, relates, 

 that a girl of nine years old, who was keeping sheep near the city of Bomst, 

 in Poland, perceiving a soldier making up to her, went to hide herself in a 

 neighboring marsh, among some bushes ; but the number of leeches was so 

 great in that place, and they stuck to her so close, that the poor creature 

 expired from the quantity of blood which she lost by their united efforts. 

 Nor is this much to be wondered at> since one of these insects, of a large 

 size, will draw about an ounce of blood. 



CLASS VI. — CRUSTACEA. 



Invertcbral animals, with a crustaceous, and more or less horny covering, pro- 

 vided with articulated members, distinct organs of circulation, and respiring 

 by bronchia:. 



The animals of this class were known to the Greeks under the name of 

 finlay.oo-Toaxo;, as designating marine animals, of which the exterior envelope 

 was much less solid than that of the testaceous, and much more so than the 

 covering of the native Mollusca. Among the Romans, this designation was 

 signified by the terms of Crustata and Crustacea, the last of which forms the 

 present name for the class. The earliest modern naturalists, like the more 

 ancient writers, arranged the Crustacea between the fishes and the mollusca ; 

 and Linnaeus placed them in his class Insecta, along with the apterous 

 insects, including the spiders in the same class. Brisson was the first who 

 formed them into a separate group. 



The Crus-tacea in one view ought certainly to occupy a more elevated 

 place among the invertebral animals, than has been assigned to them, —  

 above those, for instance, which are destitute of articulated members and 

 eyes, and where the sexual organs are in the same individual ; but, on the 

 other hand, to place them between the Cephalopodous and Gasteropodous 

 Mollusca, which would seem to be their place in the series, would break the 

 chain of connection which unites this great class. It became necessary, 

 therefore, either to place the Crustacea before molluscous animals, or after 

 them, and this last alternative has been adopted by modern zoologists. The 

 Crustacea, besides the characters they have in common with the two follow- 

 ing classes, possess some peculiar to themselves. They respire by bronchiae, 

 or by bronchial laminss generally annexed to their feet, or to their jaws. 

 They have a distinct heart, provided with circulating vessels ; feet to the 



