216 BRITISH SPECIES OF FALSE-SCORPlONS. 



distinctly includes it in his 4-eyed group, and the species described 

 above agrees well with Leach's description and figure as far as 

 they go ; and, especially, the very peculiar submarine habitat of the 

 two, are in accordance with each other. Leach says : " Habitat in 

 Anglia occidentali inter rupes ad littora maris." Moreover, the 

 examples received from Jersey and Devonshire are identical with 

 Leach's types in the British Museum. 



The observations made (ante p. 213) in respect to the joints of the 

 first two pairs of legs in 0. muscorum also apply to the examples I 

 have examined of the present species. 



Group IT. Eyes two. 



This group comprises only two genera as yet known in 

 Britain Roncus L. Koch and Chelifer Geoffr. ad partem. 

 i. Cephalothorax entire Roncus. 



ii. Cephalothorax divided transversely by grooves into three 

 portions Chelifer. 



GEN : RONCUS, L. Koch (OUsium Sim. ad partem). 



This genus is nearly allied to Obisium and resembles it closely 



in many respects, but may be easily distinguished by having only 



two eyes ; these are small and situated one on each side near the 



fore corners of the caput. The ceplialotliorax is as long or only 



very slightly longer, than broad, and its sides are parallel as far as 



the eyes, or else slightly curved. The abdominal segments are 



eleven. Trochantin in second and third pairs of legs only. Two 



species only have been found in England Roncus Canibridgii, 



L. Koch, and R. lubricus, L. K., which may be thus distinguished 



i. Humeral and cubital joints of palpi equal, and claws of 



pincers equal to the bulb in length. 



R. Cainbridgii. 



ii. Humeral joints distinctly longer than the cubital and claws 

 of pincers longer than the bulb. 



R. lubricus. 



