420 



BULLETIN 129, UNITED STATES NATIONAL MUSEUM 



fb "b Ob 'bb 



^ i 



O (N (M C<J CI C^ 



O C30 CO 00 00 00 



>oo oo 



C^ C^ CN C 



.ZmO o o 



Diagnosis. — Three spines on 

 basal article of antenna. Lateral 

 spines of carapace simple. A tu- 

 bercle on inner margin of wrist. 



Description. — Resembles M. 

 hispidus; the carapace smooth, and 

 having only a few rounded prom- 

 inences, but narrower; the front 

 also is narrower and much more 

 produced. Preorbital projections 

 rounded. The basal article of 

 antenna bears three blunt spines, 

 one below insertion of next article, 

 one stronger at antero-external 

 angle, the third equally large at 

 antero-internal angle. Orbital 

 border with only three tubercles. 

 Lateral margins armed with five 

 almost cylindrical spines, which are 

 simple and directed almost for- 

 ward; the first and fifth are small- 

 est ; the fifth is post-lateral. Three 

 strong projections on branchial re- 

 gions. Wrist with a large tubercle 

 on inner margin ; otherwise the feet 

 resemble those of M. hispidus. 

 Sternal plastron deeply hollowed 

 anteriorly for seventh abdominal 

 segment; sixth abdominal segment 

 very wide in its anterior part. 

 Merus of outer maxillipeds longer 

 and much less deeply cut at its 

 inner angle than in M. hispidus. 



Color. — Carapace a violet brown; 

 claws and feet spotted with a 

 wine-colored violet (Desbonne). 

 The spots persist indefinitely in the 

 preserved specimen. 



Measurements . — Male, type, 

 length of carapace with rostrum 

 71, width without spines 76; dis- 

 tance across front and orbits 22 

 mm. (Desbonne). 



Range. — Porto Rico ; Guadeloupe. 



