Mr. MacLeay on some new forms q/" Arachnida. 13 



obconical and less ; fourth and fifth simple, the latter 

 shortest, and both armed on the outside with a brush, 

 while the last joint is appendiculated, pyriform, and at 

 the base on the side provided also with a brush. 



Mentum separated from the sternum by a transverse furrow, 

 elongate, triangular, with a rounded point, and subar- 

 cuated in the middle. 



Body thickish and convex. Head confluent with the thorax. 

 Cephalothorax very convex above, narrower before and 

 behind, rounded in front and truncated behind, with con- 

 vex sides. Abdomen a prolate spheroid, with a hairy mem- 

 branaceous tegument. Fusi six, two being very minute. 

 Breast plane, the segments being confluent. Feet dis- 

 similar, that is, the two last pair are very different from 

 the first pair. These are thicker, darker-coloured, and 

 have the penultimate joint on the inside armed with a 

 brush of hairs. The ungues of the feet are only two, 

 which are inconspicuous, except when greatly magnified*. 



Sp, 5. Otiothops Walckenaeri. — Otiothops cephalothorace glabro pal- 

 pisque labialibus castaneo-bninneis ; pedibus brunneo-testaceis ; abdo- 

 mine nigro hirsute. 



Long. 5 lin. 



This hard-skinned spider comes close to the genus Chei'sis 

 of Savigny, or Palpimanus of Dufour. The eyes, however, 

 here are totally different, and, moreover, very remarkable from 

 the confluence of the two hinder ones. Another singular cha- 

 racter is the first pair of feet, which ai'e palpiform, and differ- 

 ent in structure from the two last pair ; thus demonstrating 

 how in Arachnida true feet may become palpiform in the same 

 way as, more ordinarily, true palpi become pediform. The con- 

 version of the organs of the mouth into organs of locomotion, 

 and again of true feet into organs of manducation, is a sin- 

 gular characteristic of certain apterous Annulosa. Otiothops, 

 Uke Chersis, has strong points of affinity to the saltigrade spi- 

 ders. Our specimen is a female. 



Walckenaer, as an essential character of spiders, lays stress 

 on what he calls the eight feet, that is, the labial palpi and 



* Their structure, highly magnified, is figured by Walckenaer in his 

 beautiful work, tab. 10. 



