162 Mr. A. Tulk on the Anatomy 0/ Phalangium Opilio. 



tusely triangular point. Internal to this piece is a second (Z>), 

 holloAved out within, and of a prominent and nearly hemispheri- 

 cal form, u])on the surface of which are scattered tuberculated 

 bristles, directed for the most part outwards. To the inner 

 edge of the above, which is oblique and somewhat sinuated, the 

 membranous fold of the second pair of maxilla (c) is connected. 

 It is densely clothed with hair, excepting towards its free margin, 

 which is cm'ved upon itself as it approaches the median line, and 

 becomes continuous with the inflected borders of the labium 

 {PI. III. fig. 11. d). Externally it is strengthened and supported 

 by an elongated cartilaginous piece [e), formed by a deflection of 

 the first-named ridge. The margins of the jaws are also con- 

 nected to each other, so that all horizontal action between them 

 is thereby prevented. 



Situated behind the above organs, and occupying in length 

 the space intervening between the coxre of the two middle pairs 

 of legs, is a broad and nearly quadrate labium (PI. III. figs. 8, 11, 

 and 13. C). Its anterior half is thin and membranous, and presents 

 a bilobed deflexed margin, while its posterior moiety is opake and 

 coriaceous, and is attached to a narrow transverse piece (PI. III. 

 fig. 13. a), united laterally with the apices of the third pair of 

 coxal joints. This last is broad at either end and constricted in 

 the middle, and is inflected twice, to form corresponding ridges 

 within. The margin by which it articulates with the labium is 

 crescentic. 



There now only remain to be noticed, as completing the instru- 

 menta cibariu, two elongate, obtuse and conical pieces (PI. III. 

 fig. 14. a), which are prolonged forwards and inwards from the 

 coxse of the second pair of legs. Their base presents a free out- 

 line, separated by a slight constriction from the sm'face of the 

 latter joints, and their margins are membranous. They are beset 

 mth long black bristles placed upon tubercles. By either side of 

 their base these pieces are in contact mth the first and third 

 coxse, their posterior margin lies in front of the sternal lip, and 

 their apices rest against and upon the sides of the labium (PI. III. 

 fig. 8. D). 



The abdomen of Phalangium (PI. III. figs. 1 and 2.) is ovoid 

 in form, convex both above and below, but more so upon itte 

 upper aspect, and narrowed slightly towards its posterior extre- 

 mity. It presents faint markings of segments, which, though 

 less distinct in the present species than in some others, as P. Cor- 

 nutum and P. quadridcntatum, are sufiiciently indicated upon the 

 dorsal surface, where they are least apparent, by transverse rows 

 of dark tuberculated bristles and slightly impressed lines, the first 

 of these corresponding Avith the middle, the latter with the in- 

 flected margins of the arcs. The fii'st and second of the dorsal 



