NO. 3536 



DECAPOD CRUSTACEANS CHACE 



649 



female without eggs, 4.7 mm.; of ovigerous females, 4.2 and 9.8 mm.; 



of juvenHe, 2.1 mm. 



Remarks- Although the St. Helena specunens closely resemble the 

 variable Acanthonyx petwerii H. Milne Edwards, 1834, from tropical 

 waters of the western Atlantic and eastern Pacific, and A. lunulatus 



Figure 12— Acanthonyx sanctaehelenae, male holotype: a, dorsal aspect of crab, right half 

 denuded; b, suborbital and buccal regions; c, right cheliped; d, abdomen; e, propodus 

 and dactyl of right posterior leg;/, caudal aspect of right gonopod; g, tip of same. 



(Risso, 1816) from the eastern Atlantic and Mediterranean (fig. 13), 

 I believe that they represent a distinct species. In the general con- 

 figuration of the carapace, A. sanctaehelenae seems nearest to A. 

 lunulatus, but apparently it can be distinguished from that species by 

 the broader, more pear-shaped carapace and the V-shaped, rather than 

 broadly U-shaped, smus between the rostral horns. 



