242 APPENDIX F. ABACHNIDIANS. 



The entire length, from the tip of the chelicerae to the end of the 

 abdomen, is one inch and a quarter, the abdomen itself forming about 

 one-half of that length. The cephalothorax is composed of three dis- 

 tinct segments ; the anterior one much the largest, giving points of 

 attachment to the parts of the mouth, to the palpi, and the two anterior 

 pairs of legs ; to the second thoracic segment is attached the third pair 

 of legs, and to the third segment the fourth pair. The anterior segment 

 of cephalothorax, seen from above, is subrhomboidal and smooth. At 

 its anterior margin are situated the two ocelli, separated from each 

 other by a deep groove. The chelicerse are very stout, and composed 

 of one single joint densely covered with setose hairs, and terminated 

 each by two spines, one above (finger of some authors,) rigid, and 

 another below (the thumb,) moving vertically against the upper. The 

 latter is compressed, acute, almost rectilinear, and smooth ; the inferior 

 one is subcorneal, curved upwards, acute towards the point, and pro- 

 vided at its base inwardly with two spiny small processes. The palpi 

 are proportionally robust, stouter and longer than the three anterior 

 pairs of legs ; somewhat shorter than the fourth pair, but of a stouter 

 appearance, as all the joints, four in number (the maxillae excepted) 

 preserve the same diameter. They are covered on their whole length 

 with hairs similar to those on the chelicerae. The maxillae are subtri- 

 angular, provided only with brushes of hairs. The next joint (the joint 

 of the palpi) is very small and triangular; the second is the longest; 

 the third is the next in length ; then the fourth, the tip of which ex- 

 hibits a minute smooth tuberculiform knob. The first pair of legs is 

 the most slender of the thoracic appendages, and about the length of 

 the third pair ; the basal joint is quite short ; the second is the shortest 

 of all ; the third is the longest ; the fourth, fifth, and sixth smaller in 

 the order enumerated. The last joint terminates like the palpi, bluntly. 

 This anterior pair of legs is called by some second pair of palpi, upon 

 the ground that their structure is most alike. The three remaining pairs 

 of thoracic appendages are seven-jointed, thus composed of one joint 

 more than in the first pair and palpi, and furthermore terminated by 

 two minute curved claws. The first, second, and third joints are short, 

 stoutish, and subequal ; the remaining are longer and slenderer, the 

 fourth being the longest, and the other diminishing gradually. They 

 are covered upon their whole length with hairs similar to those which 

 cover the palpi, but perhaps less densely so. The abdomen is subovoid, 

 being a little depressed ; it is densely hairy above and below, and com- 

 posed, as usual, of nine segments or annuli. 



Collected on June the 10th. 



