CETTSTACEA 01* THE MEBGtJI AECHIPELA&O. 115 



maxillipeds, and. even of the abdomen. Stimpson mentions 

 a ridge on the subhepatic region, proceeding parallel to the 

 inferior orbital margin. In Gi. acutus, as in G. Dussumieri, 

 I observe a glabrous groove, immediately below the inferior 

 orbital margin, running parallel to it, and separating this mar- 

 gin from the convex, hairy pterygostomian regions. But as I 

 have already remarked, this groove is proper to both forms, 

 and will probably be found in many other species of the genus. 



G. acutus therefore closely resembles G. Dussumieri in the 

 form of its cephalothorax. 



As regards the occurrence of the larger chelipede on the 

 right or on the left side : in thirty-four specimens, twenty-one 

 have it on the right and thirteen on the left side of the cephalo- 

 thorax. 



In its outer appearance the larger chelipede of the male is 

 similar to that of G. Dussumieri, and bears the same propor- 

 tioD to the cephalothorax. The three margins of the arm are 

 granular, and the convex outer (posterior) surface of the arm 

 is also covered with small granules ; the concave inner surface is 

 smooth and a little hairy, but the anterior surface is smooth and 

 glabrous. The carpopodite is similar to that of G. Dussumieri, 

 its rectangular upper surface being covered with small granules 

 fringed with hairs along the anterior margin. The hand is even 

 a little more developed than in G. Dussumieri, so that if 

 G. acutus attains the same size as that species, its larger hand 

 will probably also become twice as long as the distance between 

 the external orbital angles of the carapace. The height of the 

 hand (i. e. of the palm) sKghtly exceeds a third of the length, 

 so that the hands of the two species much resemble one 

 another in this character ; but the fingers are less elongate and 

 shorter in proportion to the length of the palm. In G. acutus 

 the fingers are but little longer than the palm, whereas in equally 

 large specimens of O. Dussumieri the fingers are once and a 

 half as long as the middle length of the palm. The outer 

 surface of the palm is granulated in the same manner as that 

 of G. Dussumieri, and the upper margin also presents two rows 

 of small acute granules, close to one another. 



The immobile finger tapers regularly towards its extremity 

 and is considerably curved upward; its outer surface appears 

 smooth to the naked eye, but minutely granular with the aid of a 



8# 



