Order 1. 



PULMONAEIA. 



453 



have not been adopted as the ground-work of this arrangement, Chelifer and Scorpio 

 being united together, whilst in the fifth order we find the " Mites " (but no definition 

 is given to enable us to judge what group is thereby intended) separated from the 

 remainder of the Acarides, which form the sixth order. 



In this valuable work the author proposes to treat of all the Apterous insects, exclu- 

 sive of the Crustacea ; but the first volume only is yet published. Distinguished as 

 its author has long been for his vmtings upon the Arachnida *, the present work, form- 

 ing a portion of the Suites a Buffon, is very valuable, as containing a mass of mate- 

 rials never before published, with the substance of the various works which the author 

 has already given to the world. Much interesting detail relative to the habits of 

 these animals is here collected, and a great number of species as well as genera of 

 Sniders, are described in this volume.] 



THE FIRST ORDER OF ARACHNIDA,— 



PULMONARIA, (Unogata, Fabricius),— 



Possesses, as above stated, a system of circulation well defined, and pulmonary sacs, ah\^ays 

 placed beneath the belly, and externally indicated by transverse orifices {stigmata), sometimes 

 eight in number, four on each side, but sometimes four or only two in number. The number 

 of simple eyes is six or eight f, whilst in the following order there are not more than four, 

 often two, sometimes very indistinct or even wanting. 



The heart is a great vessel, e.xtending the whole length of the back, and emits branches on 

 each side, and in front. J The legs are constantly eight in number. The head is also sold- 

 ered to the thorax, and exhibits at its anterior and upper extremity two claws, (mandibles of 

 authors, but named chelicera or antennal claws by Latreille,) terminated by two fingers, one 

 of which is moveable, or by a single one, which forms a moveable hook.§ The mouth is 

 composed of a labrum, (see the general observations on the class) ; two palpi, sometimes 

 having the appearance of arms or claw- legs ; two or four maxillae, composed, when there are 

 only two, of the basal joint of the first pair of legs; and of a tongue of one or two parts. || 

 By taking, as the ground of classification, the progressive diminution of the pidraonary sacs 

 and spiracles, the Scorpions, in which there are eight, (whilst there are only four or two in 

 other Arachnida,) ought to form the first genus in the class ; and hence our family Pedipalpi, to 

 which it belongs, ought to precede that of the spinning species (Araneides), which arrange- 

 ment I adopted in my Families Naturelles, and Dufour also is of a similar opinion. But 

 these last Arachnida are in some respects isolated, in consequence of their male organs of 

 generation, the hook of their frontal claws, their abdomen pedunculated, the spinnerets, and 

 their habits. The Scorpions, moreover, seem to form a natural passage between the pulmonary 

 Ai'achnida and the family of the Pseudo-scorpions, the fii'st of the followmg order. We 

 therefore commence with the Spinning Arachnida. 



• See his Faune Parisifvtif, Insectes, f. 2 ; Tableau des ^raneides, 

 1805, 8vo ; the Faune Fraitqaisf, and M^mtjire sur une Xuuvelte 

 Classification det Araneides, in the Annals of the Entomological 

 Society of France. 



t Tessarops, Rafinesque, is described as having only four eyes, but 

 I suppose the lateral ones were overlooited. See Eresiie. 



t According to M. Marcel de Serres, the blood in the Spiders and 

 Scorpions is carried first to the respiratory organs, and thence, by 

 peculiar vessels, lo the different parts of the body. But from analogy 

 with the Crustacea, the circulation is probably effected in the reverse 

 manner. (See Treviraiius on the anatomy of tliese animals.) 



§ These organs consist of a swollen basal joint, of which one of tlie 

 superior angles (when the claw is didactyle], is produced, forming 



the fixed thumD, and of a second joint, which constitutes the move- 

 able piece, either as an opposed finger or as a simple hook. 



II Tliat of the Scorpions appears to consist of four pieces in the shape 

 of an elongated, pointed triangle, produced in front ; but the two lateral 

 ones are evidently formed of the first joint of the two fore-legs, and 

 may be considered as two maxillae analogous to the two first ntaxills. 

 In Mygale, Scorpio, &c., the palpi are 6-jointed, the first joint of which, 

 in the other Spiders, is dilated to form the maxillary lobe. This lobe, 

 even, in some species, is articulated at its b.ose. If we pass over this 

 joint, the palpi are only 5-jointed, as ordinarily described. In the 

 Scorpions the terminal moveable finger of the claws forms, as in tbe 

 claws of the Crabs, a sixth joint. 



