CRUSTACEOLOGY. 



417 



Arachni- 

 tes. 



Onilio. 



Genus XXIV. Phalangicm, Linn. Fabr. Latr. 

 Herm. Don. ; Opilio, Herbst. 



Mouth consists of a labriform rostellum ; two mandi- 

 bulae and palpi ; six parts which appear to be maxillae ; 

 a labium and sexual vagina. 



Rostellum labriform, horny, short, conic, and insert- 

 ed under the mandibules, above the maxillae, in the 

 middle of the origin of the palpi ; the apex acuminated. 

 Mandibular porrect, horny, somewhat cylindrical, 

 compressed, elongate, double-jointed, inflexed at the 

 second joint, inserted under the middle of the interior 

 margin, being longitudinally contiguous ; the apex 

 armed with a forceps ; the chelae conic and equal ; the 

 thumb or external chela moveable. 



Palpi inserted at the base of the first maxillae, under 

 the origin of the mandibular ; they are composed of five 

 joints, which are nearly filiform, the third being ex- 

 cepted, which is cylindrical ; the first very short, the 

 second and last longer, the third shorter and nearly 



conic. . 



Maxillae (organs resembling them in form) placed in a 

 double order, closing the aperture of the mouth by meet- 

 in o- transversely ; they are very short and membrana- 

 ceous ; the four upper ones vesicular and intumescent, 

 with the base somewhat cylindrical and thickened; 

 the apex rounded and hairy ; a small, erect, conic, 

 needle-like process at the base of the upper pair ; the 

 lowest pair narrow, elongate, lanceolate, and slightly 

 connected together, arising from the origin of the se- 

 cond pair of feet, and resting on the apex of the sexual 

 vagina. 



Labium concealed by the maxillae ; on dissection it is 

 quadrate and membranaceous, the apex being rounded, 

 with the middle notched. 



Vagina sexual, including the sexual organ of the 

 male and oviduct of the female, is placed under the 

 maxillae, causing a prominence on the middle of the 

 pectus, resembling a sternum. 



Body somewhat orbicular or oval, covered by a soft 

 semicoriaceous skin, the breadth rather exceeding the 

 height. 



Thorax semicircular, with a tubercle on the middle 

 towards the hinder margin, on winch the eyes are pla- 

 ced, one on each side. 



Abdomen folded or wrinkled beneath. 



Feet eight, very long and narrow ; the second pah- 

 longest, then the fourth, next the third and first. The 

 conae composed of three, the tibiae of two joints ; the 

 tarsi of several, the basilar or first one longest ; nail 

 small, horny, and bent, placed at the extreme apex. 



* The second pair of feet about six times longer than 

 the body ; all the tarsi hair-like ; the inferior joints 

 elongate, four times as broad as long. 



Sp. 1. Opilio. The eye-bearing tubercle with a 

 double crown of little spines ; body oval ; thighs dis- 

 tinctly bearing spines disposed in many longitudinal 

 series ; back cinereous or testaceous, the middle of the 

 abdomen blackish ; the spines of the eye-bearing tu- 

 bercle very conspicuous ; eyes rather distant ; the space 

 of the thorax passing them not abruptly elevated ; an- 

 terior tibiae angulated (of the female with a groove) ; 

 second joint of the palpi generally with a blackish or 

 obscure spot. 



Male, Phnlangium cornutum, Lin. Fab. Hermann. 



Female, Phalangium opilio, Linn. Fab. Hermann. 



Inhabits Europe, is frequent on walls or amongst 

 grass. The male has the second joint before the apex 



VOL. VII. PART ir. 



of the mandibles transversely and longitudinally fixed Arachnri 

 to the preceding ; and palpi as long as the body. These des ' _, 

 sexual distinctions (which most probably apply to the ~" '' 

 whole genus) were observed by that celebrated obser- 

 ver of nature Geoffroy. 



Observation 1 . Latreille says, that he has observed a 

 species much allied to Phalangium opilio, differing, how- 

 ever, by having the anterior feet nearly cylindrical, and 

 not distinctly angulated, and the third and fourth 

 joints of the palpi, especially the former, produced at 

 the apex internally into a horn or branch, as in Pha- 

 langium uncato of Hermann, (Mem. Apter. page 106, 

 plate 8, fig. 5,); the second joint of the same colour 

 with the rest ; the upper part of the body somewhat 

 nut-coloured, with paler spots ; the back not black in 

 the middle ; the thighs less spiny. It appears to be 

 nearly allied to Hermann's species above alluded to ; 

 the individual mentioned by Latreille was a female. 



Observation 2. Opilio longipes, Herbst. (Naticrg. opil. 

 tab. 2. fig. 2.) is distinguished from Phalangium opilio 

 by its pale nut-colour without the black dorsal mark ; 

 by the shorter spines of the eye-bearing tubercle ; the 

 eyes more approximated, reddish, with a black spot in- 

 terposed ; the space before them abruptly elevated ; the 

 second joint of the palpi of the same colour with the 

 rest ; the anterior tibiae cylindrical and somewhat spi- 

 nous. This is supposed to be a mere variety of Pha- 

 langium opilio by Hermann. 



Observation 3. Phalangium cornigerum of Hermann, 

 is readily distinguished from the male of Phalangium 

 opilio, by its spiny palpi, the internal apex of the third 

 and fourth joints prominent ; the second joint of the 

 mandibides before the apex near the chelae elevated in- 

 to a horn above. Latreille thinks this may be the male 

 of Phalangium uncatum. 



Sp. 2. Rotundum. The eye-bearing tubercle smooth Rotun- 

 and black ; body orbicular-oval, above testaceous, the dum. 

 dorsum testaceous, that of the female with a black spot 

 of a quadrate form, spotted with pale colour ; base of 

 mandibules with two teeth on the upper part; feet 

 very slender and black, the extremities of the joints of 

 the thighs and tibiae generally whitish. 



Phalangium rotundum, Hermann, Latreille. 

 Inhabits France, is common in a wood called St Ger- 

 main, and at Petit-Gentilly. It has once occurred in 

 Scotland, in Ravelston wood, near Edinburgh ; it is 

 probably rare in Britain. 



** Second pair of feet three, four, or more times as 

 long as the body ,• tarsi with the fourth, fifth, and 

 following joints a little elongated, twice as broad 

 as long. 

 Sp. 3. Histrix. The eye-bearing tubercle a little Histrir. 

 elevated, obscurely crowned with granulations ; body 

 quadrate-oval, the back cinereous or yellowish-grey ; 

 the coxae and sides of the thorax spiny ; the middle of 

 the anterior margin itself, with three porrect close-set 

 spines ; feet pale yellowish, with obscure spots ; the 

 tibiae angular ; tarsi with thirty joints or more. 

 Phalangium histrix of Hermann and Latreille. 

 Inhabits France and Britain ; it is a common species, 

 frequently occurring under stones, on walls, &c. The 

 female has a quadrate black spot on its back. Phalan- 

 gium cristatum of Olivier (Encyclop. Mclhodique), and 

 Opilio hispidus of Herbst. (tab. 3. fig. 1, 2.), belong to 

 this division. 



Sp. 4. Quadrideniatum. The eye-bearing tubercle Quadriden- 

 and base of the palpi and feet spiny; body oval, de- tatU! "- 

 3g 



