466 



4IIACIINIDA. 



mined. Each of the four following segments has a pair of puhiionary sacs and spiracles. Immediately after the 

 si.xth segment, the abdomen is suddenly nari-owcd, the six terminal knotted joints forming; the tail. The tarsi are 

 alike, and 3-jointed, with two terminal ungues. The two nervous cords rimniug from the brain are united at in- 

 tervals, forming seven ganglions, of which the tenninal ones belong to the tail. For further details of thr anatomy 

 of these animals, consult the works of Treviranus, M. de Serres, and Leon Oufom (Jourii. de F/ii/sirpie, 1817). 



These Arachnida inhabit the warm countries of both hemispheres, living in the ground, hidmg themselves 

 anler stones or other bodies, generally amongst ruins, or other dark and cool places, and even in the intenor of 

 houses. They run quickly, and curve the tail over the back. They cau turn it in all directions, and employ it as 

 an arm of defence or olleuce. Tiiey seize Wooil-lice, and other ground insects, such as Carabi, Weevils, Ortho- 

 ptera, &c., which serve lliem as food, with their pincers, pricking them with their stings, and then carrying them 

 to tlieir month. They are also particularly fond of the eggs of Spiders and other insects. 



The wound occasioned by the sting of the Scoifiio europams is not, as it appears, ordinarily dangerous. That 

 of tlie Scorpion of Souvignargues, of Maupertuis, or of the species which I have named Occitanus, and which is 

 more powerful than that of the preceding, produces, according to experiments which Dr. JIaccary hatl the courage 

 to try upon hi]nself, more alarming effects. The poison appears to increase in power according to tbe age of the 

 animal. Volatile alkali, either applied interiorly or exteriorly, is used to counteract its etl'ects. 



Some authors assert that the indigenous [French] species produce two broods in a year, but it appears more 

 correct to consider that this takes place in the month of August. According to JIaccary, it changes its skin before 



coupling. The female cairies her young upon her back for 



several days, at first not quitting her abode at such time, and 



/I'' ^^.^zx^" takes care of them for the space of a month, by ^\hich time 



they are able to shift for themselves 



Some have eight eyes, forming Leach's genus Biithus. 

 'Scorpio ofer^ Linn., which is five or six inches long, and in- 

 habits the East Indies, Ceylon, &c. S. occitanus, Amorou-x, 

 {Tiinetanus, Herbst.) I\Iiddle of Europe, Barbaiy, Spain, &c. 

 Tlie others have only six eyes, forming the restricted genus 

 Scorpio of Leach. .S". eurojwus, Linn., Fab., Herbst. South 

 of France. 

 fThe genus Scorpio, Linn., has been revised by Hemprich and Ehrcnberg in tlicii- great work upon the animals 

 of Arabia, and many new genera and subgenera separated therefrom. IMany new species have also been recently 



described by Koch, in the continuation of Hahn's Die Aracfi/iideii.'] 



THE SECOND ORDER OF ARACIIiNIDA — 



TRACIIEARLE,— 



Differs from the preceding in the respiratory or!i;ans, wliich consist of radiating; or raniitied 

 tracheie'^, wlneli only receive the air by two sjiiraeles; in the absence of a cireuhitiug: origan f, 

 and in the niimher of the eyes!};, which is oidy two or fonr. From the want of snfticientlv 

 generalized anatomical observations, tlie hniits of this order are not rigorously determined. 

 Some species, indeed, of these Arachnida — such as the Ppcnof/onidce — do not exhibit any 

 spiracles; and their mode of respiration is unknown. 



The tracliean Arachnida arc naturally divisible into those provided with ehelieerix- terniinnted 

 by two tinL';i'rs, one of whieli is moveable, or by a single one, equally moveable, m the form of 

 a lii)(d<, and those where these organs are replaced by sim[tle plates or lancets, which, together 

 wi(h the tongue, conijiose a sucker; but the majority of these animals being minute, their 

 examination is attended with very great dllticulties, so that these characters ought only to be 

 resorted to when it is impossible to adopt others. 



' 'I'lie trnchete Bre vusS' 

 Gini\ ill (.-very part of llie 

 w^iiit of circulation. They 

 of three nicmbrHnea, the i 



•An which receive ftud distribute tlic aeritil 

 interior <*( the hcidy, miiJ llius remedy the 

 Fire of two kinds.— tuhultir or elastic (formed 

 iiiddle one conipoaed of a spirnl thread), mid 



riieous, niuveabic pl.iics. ond arc peculiar to 

 2 aquatic larvie \ui\c a very peculiar reapiratory 



vesicular, formetl of only two nienibrnnes these form a kind of pneu- 

 matic reservoir, capable of infliition, communicating with each otlicr 

 by nicann of tubular tracbcic. The trachcie are divided into two prin- 

 cipal trunks, extending aloiitr the BidcB of the body, and receiving the 

 a.lr by orifices or Kjiirncles. There are also, in many iDsccts, two otlier 

 lonKitudiniil trunks, situated between the preceding, with which they 

 coaimunictile, and which SerrcN calls pulmonary tritcheEe, giving to 

 the ordinary oneii the name oi arterial tnielicie. He also ditjtingiiislics 

 Wiv kind of spiracles ; the common onea are closed by menibranima 

 lipa, opening by simple contraction the others, named tremaferea by 



Serres, are shut by 

 some Orltimptcra. So 

 apparatus. 



t The presence of traclu-ni excludes all cumplete circulation,— that 

 is, the {listribution of the i)U>od to different iiarts. and ils return from 

 the orj,'rin8 of respiration to the heart. Hence, although certain vessels 

 have been discovered in some Insects {Phasuia), and their existence 

 is possible in the traclienn Arachnida, these creatures do not the leai" 

 enter into the general system. M. M, de Serres has observed thnt the 

 intcstintl canal of Phalangium emits a very great number of ca'Cums, 

 or vermiform appendages, which appear analogous to hepatic vessels, 

 and that the trachea: ramify most eiteiisively upon these cn?cnm3. 



t Accoriiint; to Muller, Hydrachna umbrata bus sii eycB ; but \e not 

 this a mistake^ 



