CARCINOLOGICAL STUDIES. 37 



as those of Gelas. Dussumieri; they are smooth and as 

 strongly compressed on the outer as on the inner surfaces. 

 The outer surface of the lower finger is longitudinally fur- 

 rowed and this furrow proceeds close to the lower 

 margin of the finger; in Gelas. Dussumieri this fur- 

 row proceeds quite on the middle of the outer surface of 

 that finger. The outer surface of the upper finger or dac- 

 tylus is also faintly furrowed and the furrow proceeds on 

 the middle of the finger. Whereas the immobile finger of 

 Gelas. Dussumieri presents a prominent conical tooth a 

 little before the middle, the inner margin of the lower 

 finger of Gelas. signatus is armed with a broadly tri- 

 angular lobe or tooth of a characteristic form 

 at some distance beyond the middle (fig. ll''); in the 

 larger specimen the distance between the tip of this lobe 

 and the extremity of the finger is distinctly shorter than 

 the distance between the tip of the tooth and the base of 

 the finger , but in the smaller specimen , the fingers 

 of which are a little shorter in proportion to the length 

 of the palm, the tip of the triangular lobe lies exactly as 

 far from the base as from the extremity of the finger. The 

 upper finger or dactylus has exactly the same form as that 

 of Gelas. Dussumieri and the same dentition : I observe 

 one small granule immediately before or opposite the tip 

 of the large lobe of the index, and three or four granules 

 near the proximal end of the finger. 



The ambulatory legs present about the same form in 

 both species. 



The cephalothorax of these two specimens has a dark 

 green colour; arm, carpus and palm of the larger chelipede 

 are yellowish red , the fingers white. 



The larger individual has the following dimensions: 



0^ 

 Distance between the external orbital angles. . 21 mm. 

 Length of the carapace (the front included) . . 12'/2 » 



Length of the larger hand 34 » 



Length of the fingers 24 » 



Notes from the Leyden Museum, "Vol. XIII. 



