44 Mr. R. I. Pocock on 
CHELOCTONUS, gen. nov. 
(PISMO. fie. 4.:) 
Cephalothoraxz with its median eyes near the middle, the 
lateral eyes, three in number, on the very edge, as in Hor- 
MUTUS. 
Sternum pentagonal, a little wider than long, narrower at 
its posterior angles. 
Stigmata elongate. 
Tail as in Opisthacanthus, rather stouter than in Hor- 
murUus. 
Palp.—Humerus as in Heterometrus maurus, very convex 
above, the anterior border reduced to a minimum; manus 
intermediate in form between that of, e. g., Opisthacanthus 
and of, e. g., Scorpio, but rather resembling that of Zurus or 
Urodacus in having the ‘‘ hand-back ” double, 7. e. divided 
longitudinally by the keel which is found on the hand-back 
in scorpions of this group ; the lower half of this area is not, 
however, limited below by a keel, and the keel that defines 
the upper half is weaker than in Opisthacanthus. 
Chelicere as in Opisthacanthus, Hormurus, and Palam- 
neus, 1. e. with the terminal fangs of the movable dactylus 
subequal in length, the inferior being the longer. 
Tail, tarsi, stigmata, and pectines as in Opisthacanthus. 
This genus is very interesting on account of its annectent 
qualities. On the whole, however, it certainly belongs to 
the Opisthacanthus group, although in the form of its palpi 
it approaches Heterometrus. 
Cheloctonus Jonesit, sp. n. 
Colour olivaceo-piceus above, palpi darker; legs, cheli- 
cere, and caudal vesicle ferruginous ; pectines and genital 
operculum testaceous. 
Cephalothoraw a little wider than long, a little longer than 
the first two caudal segments, convex from side to side, the 
sides being considerably sloped, the frontal lobes rounded, 
the middle of the anterior border with an evenly rounded 
excision, weakly granular, the median sulcus dividing the 
ocular tubercle and stopping almost immediately behind it ; 
the tubercle low, situated just in front of the middle of the 
upper surface, the eyes separated by a space about equalling a 
diameter ; the lateral eyes small, subequal, the two anterior 
contiguous, the posterior separated by a space equal to its 
own diameter. 
Tergites finely and closely granular, sulcate as in Opistha- 
canthus. 
