APPENDIX F. ARACHNIDIANS. 239 



longer than broad, narrower anteriorly than posteriorly; both of these 

 extremities linear; lateral margin somewhat undulated. Its surface is 

 carved with a few undulating grooves, giving to the rest an undulated 

 appearance ; and over the whole, minute granules. The median ocelli 

 are black, situated a little in advance of the middle of the length of the 

 thorax, and placed on the sides of an elongated, little, and black emi- 

 nence, divided longitudinally by a groove. The lateral ocelli are set 

 close together, and situated near the anterior margin of the cephalotho- 

 rax ; the posterior one is much the smallest : they are represented with 

 their relative proportions in fig. 7. The cheliceraa are stout, two- 

 jointed ; the second being the largest, and is terminated by a minutely 

 .serrated claw; the palpi are five-jointed; the first joint is short and 

 stout, and fulfils the function of jaws without denticulation. The second 

 is the smallest. The third and fourth are more elongated ; the third 

 a little longer than the fourth. They are angular, the angles being 

 margined with dense rows of minute granules. The fifth joint or hand 

 (carpus) is stout and swollen, exhibiting eight undulating ribs, (four above 

 and four below), upon which is a row of minute granules. Two rows 

 above and below are seen extending along the spiny immovable pro- 

 cessus of the hand, constituting, with a movable spine, a slender chela or 

 claw, slightly curved inwards. Scattered setae may be seen on the whole 

 length of the palpi ; and also on the thoracic appendages (feet.) The 

 latter are slender; the fourth pair is the longest; the first pair the smallest, 

 the second and third pairs being of intermediate proportions ; the second 

 longer than the first, and the third longer than the second. They are 

 all flattened, seven-jointed, and terminated by minute hooks. The third 

 joint is in every one the longest and most slender ; the fifth, sixth, and 

 seventh are small, the seventh being the smallest of all. There are 

 generally three terminal hooks ; occasionally minute spines may be seen 

 near the articulation of the sixth and seventh joints. The first joint is 

 the stoutest, and in the first pair of these appendages it has something 

 to do with mastication, functioning perhaps as a lower lip. The 

 abdominal combs are slender and elongated, and composed of a trans- 

 verse tri articulated piece, and .of eighteen little laminse attached to it. 

 The dorso-abdominal shields, seven in number, increase in size from 

 forwards backwards, the anterior one being the narrowest of all. Their 

 rurface exhibits minute granules not very conspicuous. There are only 

 five ventral shields, nearly equal in size ; the posterior one somewhat 

 different in shape, and not provided with stigmata. The caudal ap- 

 pendage (tail) is as long as the body, and composed of five joints and a 

 poison bag. The two first joints are the smallest, the fifth being the 



