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Stat. 311. February 12/13. Sapeh-bay, East coast of Sumbawa. Reef. 1 specimen of medium 

 size, probably a male. 



It is rather incomprehensible that Coutière in his diagnosis, in which he only deals with 

 the shape of the two chelae of the i st pair of legs and with the coloration, does represent 

 this species as related to A. socialis Heller from New Zealand, the characters of which are 

 quite different and to which A. barbatus resembles not at all. I am very much obliged to 

 Professor Coutière for having enabled me to examine the type specimens of A. barbatus, 

 collected by him at Djibouti, (two specimens without the legs, four larger chelipeds, one small 

 cheliped of a male and one of a female, and legs of the following pairs). The examination 

 of these specimens proved that A. barbatus is not only characterized by the shape of the first 

 pair of legs, but also by that of the following and by the features of the rostrum and of the 

 two pairs of antennae. 



Unfortunately no adult or egg-bearing specimens were collected by the "Siboga" and 

 in all the specimens collected the smaller cheliped is missing. 



The larger of the two type specimens from Djibouti, an ova-bearing female, is 22,5 mm. 

 long, while the largest specimen captured by the "Siboga", that from Stat. 311, is 15,5 mm. 

 long. It is from this specimen that the following description is taken. 



Width of the orbital region two-thirds that of the anterior margin of the carapace. Rostrum 

 short, obtuse, hardly reaching beyond the middle of the visible part of i st antennular article, 

 twice as broad at its base as it is long. Anterior margin of the orbital hoods rounded, unarmed. 

 Interorbital carina obtuse, separated by moderately broad and shallow grooves from the orbits, 

 beyond the base of which it does not extend. 



Abdominal pleura rounded inferiorly. Greatest width of the telson slightly more than 

 half its length, distance between the postero-lateral angles' just half as broad as the greatest 

 width. The two pairs of spinules on the upper surface are very small, the anterior pair 

 one and a half as far distant from the base of the telson as from its posterior margin ; sub- 

 terminal spines also very small. 



Second antennular article almost as thick as longr and one and a half as lone 

 as the visible part of the first ; 3 rd article as long as the 2 nd . Stylocerite rounded, as 

 longf as i st article. 



Basicerite unarmed, carpocerite stout, co nsider ably long er than the antennular 

 peduncle, extending beyond the tip by somewhat more than the length of 3 rd article; scaphocerite 

 2,5-times as long as broad, narrowing anteriorly, the terminal spine extends by one-fourth of its 

 length beyond the blade and the outer margin is straight. The scaphocerite, much shorter than 

 the carpocerite, is but little longer than the antennular peduncle, the blade reaching to the 

 end of the peduncle. 



In the adult type specimen from Djibouti the 2 nd antennular article appears almost 

 one and a half as long as thick, whereas the 3 rd article appears decidedly somewhat shorter. 



In the specimen from Stat. 311 the terminal joint of the external maxillipeds bears 

 several strong setae at the truncate extremity. Merus of the large cheliped half as broad as 

 long, infero-internal margin somewhat uneven, unarmed at the apex like also the upper margin, 



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