ORDER PULMONARIiE. 395 



recent knowledge of some species peculiar to hot climates, 

 such as the mason spider-, described by the Abbe Sauvages, 

 and some others analogous ; the employment of the organs of 

 manducation introduced into the method by Fabricius ; a 

 more precise study of the general disposition of the eyes, and 

 their respective sizes ; and, further, the consideration of the 

 relative length of the feet, have all contributed to extend this 

 classification. M. Walckenaer has entered in this respect 

 into the most minute details, and it would be difficult to dis- 

 cover a species which does not find its place in some one of 

 the sections which he has established. There is, however, a 

 character, the application of which has not been generalized, 

 the presence or absence of the third hook at the end of the 

 tarsi. M, Savigny has presented us in this point of view, a 

 new method, but of which I am only acquainted with a simple 

 synopsis. 



M. Leon Dufour, who has published some excellent memoirs 

 on the anatomy of insects, who has made an especial study of 

 those of the kingdom of Valencia, where he has discovered 

 many new species, and to whom botany is not less indebted, 

 has bestowed particular attention on the respiratory organs of 

 the arane'ides, and it is according to him that we shall divide 

 them into those which have four pulmonary sacs (and exter- 

 nally four stigmata, two on each side, and very near each 

 other), and into those which have but two. The first, which 

 embrace the order of arane'ides theraphosae, of M. Walckenaer, 

 and some other genera of that which he designates collec- 

 tively under the denomination of spider, compose according 

 to our method but a single one, that of 



Mygale. 



Their eyes are always situated at the anterior extremity 

 of the thorax, and usually very closely approximated. Their 

 forceps and feet are strong ; the copulatory organs of the males 



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