170 GEOLOGY AND PALEONTOLOGY OF THE WEST INDIES. 



from this small fragment, it is the same as Recent specimens. From 

 the Yaqui Valley at Cercado de Mao (Bluff 3), Santo Domingo; lower 

 Miocene; C. J. Maury, collector; 1916. 



Range. — Recent specimens range from Bahamas and west Florida 

 to the West Indies; also Cape St. Lucas, Lower California, to Panama. 



Family LEUCOSnD-E. 



Genus PERSEPHONA Leach, 1817. 



Persephona prepunctata, new species. 



(Plate 9, Figure 5.) 



Type locality. — The Yaqui Valley at Cercado de Mao (Bluff 3), 

 Santo Domingo; lower Miocene; C. J. Maury, collector; 1916. 



Material. — About 30 arm-joints, mostly incomplete. One of the 

 best is made the holotype (Cat. No. 324425, U. S. N. M.). 



Relationships. — In shape these specimens approach the correspond- 

 ing segments of P. punctata (Linnaeus) 1 but the granules are much 

 more numerous and crowded than in punctata, resembling more those 

 of P. townsendi (Rathbun), 2 from the west coast of tropical America. 



Subtribe BRACHYGNATHA. 

 Superfamily BRACHYRHYNCHA. 



Family PORTUNIDJE. 



Genus SCYLLA de Haan, 1833. 



Scylla costata, new species. 



(Plates 4 and 5; Plate 6, Figures 3 to 5.) 



Type locality. — Lower half of the valley of the Yaqui del Norte 

 River, in the northern part of Santo Domingo, Haiti; probably lower 

 Miocene; W. M. Gabb, collector. 



Holotype.— Male. Cat. No. 2267, Mus. Phila. Acad. Nat. Sci. 



Measurements. — Length of carapace (approx.) 82 mm.; width of 

 carapace 128 mm.; length of propodus of larger cheliped, above, 42 

 mm.; below (approx.) Ill mm.; height of same 41.3 mm. 



Description. — Regions of carapace separated by very shallow depressions; 

 no evidence of transverse, granulate ridges; the outer layer of shell is almost 

 entirely lacking. The margin of the front is embedded in the matrix. Inner 

 edge of orbit raised, marginate; outer tooth large, its outer margin oblique but 

 almost longitudinal. The antero-lateral teeth are probably 9 and are alter- 

 nately large and small, at least the sixth and the eighth are small, the second 

 and the fourth are not visible. The teeth are curved forward at the end; the 

 third, fifth, seventh, and ninth teeth dim nish in basal width in the order 

 named. 



Chelipeds very strong, unequal. Three spines are visible on the inner or 

 anterior margin of the merus beyond the edge of the carapace; the most distal 

 one is strong, conical, sharp; the most proximal one is smaller and more 



1 Syst. Nat., ed. 10, vol. 1, p. 630, 1758 (part). 



 Myra townsendi Rathbun, Proc. U. S. Nat. Mus., vol. 16, p. 255, 1893. 



