ORDER PULMONARLE. 
395 
recent knowledge of some species peculiar to liot 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 aranei’des, 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 aranekles tlieraphosm, ofM. 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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