136 01ST NEW CHAMELEONS FROM BRITISH EAST AFRICA. [May 21, 



Chameleon johnstoni. (Plate XIII.) 



Casque feebly raised posteriorly, with obtusely angular posterior 

 contour, with a short, feeble parietal crest ; the distance between 

 the commissure of the mouth and the extremity of the casque 

 equals the length of the buccal cleft ; lateral crest strong and 

 tubercular, but absent on the snout ; no canthus rostralis ; inter- 

 orbital region concave ; male with three long, conical, smooth, 

 horn-like processes with circular striae, directed forward and 

 slightly upward, one in front of each orbit and the third on the 

 snout ; the rostral horn a little thicker, but not longer than the 

 orbitals ; no trace of such appendages in the female ; scales on 

 upper surface of head unequal, moderately large ; no trace of 

 occipital lobes. Body with angular spine, but without crest, 

 coarsely granular, with scattered small flat tubercles ; no gular 

 or ventral crest. Xo tarsal process. Tail as long as head and 

 body, not crested. Uniform dark olive ; horns yellowish. 



millim. millim. 



Total length 224 220 



From end of snout to extremity of 



mandible 24 24 



From end of snout to extremity of casque 33 33 



Rostral horn 16 — 



Prseorbital horn 17 — 



Greatest width between lateral cranial 



crests 13 13 



Depth of skull (mandible included) 21 21 



Width of skull 17 17 



Body 88 80 



Tibia 22 20 



Tail 112 115 



Three male specimens, one female and one young. 



The Chameleon which I have the pleasure of naming after 

 Sir Harry Johnston, K.C.B., is most nearly related to the one 

 described by me as C.jacJcsoni,irom. which it is easily distinguished 

 by the more feeble occipital crest, the finer granulation of the 

 body, and the absence of large tubercles on the spine, forming a 

 dorsal crest. 



EXPLANATION OP THE PLATES. 



Pl,ATE XII. 



Chammhon xcnorhinus, male, with upper view of bead, and side view of bead 

 of female. 



Plate XIII. 



Chmnceleon johnstoni, male, with upper view of head, and side view of bead of 

 female. 



