3Ü CARCINOLOÜICAL STUDIES. 



elongate band with two small teeth , one of which stands 

 a little before the first prominent tooth of the index, the 

 other a little before the subdistal tooth of the latter. In 

 the other specimen it is not provided with prominent 

 teeth, but it presents only several granules, four or five 

 of which are larger than the others , and the largest of 

 which lies quite opposite the prominent tooth on the 

 middle of the index. The ordinary crests on the inner 

 surface of the palm are distinct and coarsely granulated. 

 The ambulatory legs are less slender than those of the three 

 preceding species; the meropodites are more enlarged in pro- 

 portion to their length, so that e. g. those o f t h e penul- 

 timate pair are exactly twice as long as broad. 



I will finally observe that Gelas. acutus Stimps. from 

 Macao and from the Mergui Archipelago , of which I have 

 published a complete description in my » Report on the 

 Mergui Crustacea" , is somewhat allied to Gelas. arcuatus 

 de Haan. The anterior as well as the ambulatory legs 

 present indeed the most striking resemblance in both spe- 

 cies, when comparing Stimpson's species with the variety 

 of Gelas. arcuatus in which the fingers of the larger hand 

 of the male are little longer than the palm. But the 

 cephalothorax of Gelas. acutus is still more narrowed back- 

 wards; the lateral margins are straight, extre- 

 mely oblique and not presenting an S-1 ike 

 course; the external orbital angles, finally, are much more 

 acute and directed very obliquely outward , projecting much 

 less forward than the middle part of the upper orbital margin. 



The measurements of the two Leyden types of Gelas. 

 arcuatus de Haan are as follows: 1. 2. 



Distance between the ext. orb. angles SGVg mm. Si','^ mm. 

 Length of the cephalothorax (front 



included) 22'/, » 20'/^ » 



Length of the larger hand ... 67 » 54^/2 » 



Height of the palm 21 » lOVg » 



Length of the fingers 46 » SSVg » 



Notes frona the Leyden Mixseum, Vol. X.III. 



