434 AKACHXIBA. 



THE FIRST FAMILY OF THE PULMONARY ARACIINIDA,— 



The Fili:l'Si-:s or Araneides, — 



Consists of the genus of Spiders, Aranea, Linn., in \\h\rh the palpi resemble small feet without a claw 

 at the tip, terminated at most iu the females hy a small huok, and of which the terminal joint incloses 

 or supporls, iu tiic mak'S, various a[)[ici](Uic:i;:^, mure or lc::;s comiilicaled, employed in generation.'^ The 

 frontal claws (maudihles of authors) arc terminated by a muveablu hook, which folds downwards, liavincr 

 on its under side, near its pointed extremity, a small sht for the emission of venomous fluid secreted 

 in a gland of the preceding joint. The masiihe ;irc ne\er im.>re than two in number ; the tongue is of 

 a single piece, always c.\tcrn;tl. and t-ituatcd between the ]iia.\ilhe, and more or le^^ square, triangular, 

 or semicircular. The ihinax j hi^s generally a V-hke imprc^siun, indicating the region of the head, 

 but consists of a single pirce, to which is posteriorly attaclieil, by means of a short peduncle, a moveable 

 and generally soft abdoniiMi. This part of the body is furnished in all the species beneath the anus 

 with four or six nipph;^, llcihy at the tips, c\lindrical or conical, articulated, closely approximating 

 together, and pierced at the extremity with an infinity of minute orifices J for the discharge of silken 

 threads of an extreme tenuity, emitted from internal reservoirs. The legs, identical in form, but dif- 

 ferent in length, arc composed of seven joints, of which the llr^t two foiin the liauneb, the next the 

 femur, the fourth § and the fifth the tibiic, and the t\vo others tlie tarsus. The lai,t la ordinarily ter- 

 minated by two ungues, generally tootherl lieiieath, and by a third smaller unguis, not toothed. The 

 intestinal canal is straight ; the first iitomaeh is composed of several sacs, and about the middle of the 

 abdomen is a second stomaeb-like dilatation. 



The nervous system is composed of a double chord, occupying the mid-line of the body, and of 

 ganglions, which distribute nerves to tlie various organs. According to Treviranus, the number of 

 ganglions is only two. The upper surface of the abdomen exhibits, especially in the smooth, naked 

 species, various impressed spots, differing in number and situation, which, according to Dufour, are 

 produced by the attachment of the filiform muscles which traverse the liver. The pulmonary orifices, 

 two or four in number, are indicated externally by as many yellowish or whitish spots near the base 

 of the belly, immediately after the segment, which, by means of a fleshy filament, unites the abdomen 

 with the thorax. Each pulmonary mass is formed by the superposition of a great number of white, 

 tri;ingnhir, extremely slender })lates, which become conlluent around the spiracles, uf which tlie num- 

 Ijcr is the same as that of the pulmonary sacs. The female Aiancide^ have two ovaries, quite distinct, 

 lodged in a kind of capsule formed by the liver. "NVith respect to tlie simple eyes, Dufour observes, 

 that they sliinc in tlie dark like tlM:)SC of the Cat, and tliat iu ctTect the Araneides can sec both by day 

 and niirht. The abdonim uf Sjiiders is subject to so great an alteration after death that its colours 

 and CM'U its fui'io ai'c not recognizable. Dufour has, however, been enabled, by means of very rapid 

 dc^iccatinu (of which he has given the prorrss), lo remedy this evil in a great degree. 



According to Reaunun-, thr silk undergdr,:, a first elaboration in two small reservoirs, like drops of 

 glass, placed obliquely, one on each siile, at the base of six other reservoirs, like intestines, situated at 

 tlie side of each other, and folded up six or seven times, and proceeding to the nipples by a very 

 slender filament. It is in these latter ves:iels that the silk acquires greater strength, and other pro- 

 perties which it possesses. On leaving tlie nl|qd(s the i.ilkeu thieads are glutinous; they require a 

 certain degree of desiccation or cva])or;Uiiin of liumiitity to fit thctu for use. But it appears that in 

 favourable weather a moment is sutheient, flic animals making use of their tlireads as soon as they are 

 iliscbargcd. The wlnte, silky masses seen lloating in the air in spring and autumn, called in France 

 fi/.\- dc la vierr/e, arc ci'rtainly [iroduced, as we have proved, liy tracing them from their point of de- 

 parture, from various yuung Spiders, especially Thomisi and E[icirx. It is also i>robablc that many of 



* Aflur .-ill Uie .jlisenatioiih \vlikli Itavc been made upun Uic 

 of s]iidcrs, 1 fitn Induced to btlievc these fippendng-ea are i 

 efriicration. 1 liave in vain •ioui'lit for any ventral orijans, ii 

 in;il.' .MvL'ivIe, t'rt.-«L-rv(.-d j[i s|jirits. We iiukIu not iilw;iys I 

 irjinii iiiiiiliiLry— iijr iiistanec, tlic female organs of rauuicris ; 

 uir siluuir'il iicrir llie mouth— ii f;ict of which thcr^ is n 



J iippliod to a iiortion only 

 ■oplerous aud Oriboplerous 



