20 



CAÏICINOLOGICAL STUDIES. 



Measurements : 

 Distiince between the ext. orb. angles 

 Greatest width of the cephalothorax, 



the swollen lateral parts of the 



body included . . , . 

 Leno;th of the cephalothorax 

 Breadth of the orbits . 

 Height » » » . . 



Length of the larger hand 



Genus Gelasiimts Latr. 



I am acquainted by personal observation with fifteen 

 Indopacific species of this genus, which may be distinguished 

 by the following characters: 

 I. Fi'ont between the eyes narrow. 

 A. liower wall of the orbits without 

 an accessory row of granules near 

 the inferior margin. 

 oi. Anterior margin of the arm of 

 the larger chelipede of the male 

 with an acute and prominent 

 tooth. Cephalothorax little nar- 

 rowed backwards. 

 /3. Orbits only a little oblique. 

 Hand internally with two 

 strongly granulated ridges, vocans M. E, 

 /3/3. Orbits very oblique. Hand 

 internally without granu- 

 lated ridges tetragonon Herbst. 



»x. Anterior margin without an acute 

 and prominent tooth. Cephalo- 

 thorax more or less strongly 

 narrowed posteriorly. 

 y. Lower finger or index with a 

 single tooth a little before 

 the middle. Hands elongate. Dussumieri M. E. 



^otes from, tlie Leytlen Museum, Vol. X!III. 



