AET. 8 CRUSTACEANS FROM MEXICO RATHBUN O 



num finely punctate and with low, flat granules. Lower border of 

 orbit, buccal cavity and abdomen not known. The merus of the 

 cheliped is massive, a cross-section near the large end is irregularly 

 oblong (pi. 2, fig. 1, left). A cross-section of a palm (pi. 2, fig. 1) 

 indicates 5 rows of spines on outer surface. A portion of a finger 

 remains; the outer margin is armed with stout spines pointing dis- 

 tad ; of 3 prehensile teeth preserved 2 are large, separated by a small 

 one; a strong ridge (either dentate or spinate) lies nearest to the pre- 

 hensile edge. The merus of the legs is elongate, slightly compressed, 

 sides subparallel, a longitudinal groove through the middle of the 

 anterior (under) side (pi. 2, fig. 3). 



Measurements. — Male holotype, median length of carapace 43, ex- 

 treme length of carapace 46.3, width of carapace 45.6, fronto-orbital 

 width 15 mm. 



Occurrence. — Lower California : Ranchito on south side of Arroyo 

 Colorado between ranches Matanzo and Colorado; upper Eocene; 

 November 11, 1920; Cat. No. 371095, U.S.N.M. 



Family PORTUNIDAE 



SCYLLA COSTATA Rathbun 



Plate .3 



Scylla costata Rathbun, Publ. 291, Carnegie Inst. Washington, 1919, p. 

 170, pis. 4 and 5, pi. 6, tigs. 3-5; Dominican Republic, probal)ly Lower 

 Miocene. — Withers, Ann. Mag. Nat. Hist., ser. 9, vol. 14, 1924, p. 229, 

 pi. 6, figs. 1 and 2 ; Anguilla, Upper Oligocene. 



Two right chelae of small specimens, palms respectively about 30.8 

 and 22.3 long, measured from the interdigital sinus along middle of 

 palm. The larger chela has a palm similar in shape to that of the 

 holotype, while the smaller one (pi. 3) is squarer, approaching that 

 figured by Withers. 



Occurrence. — Mexico; origin obscure. Original numbers 201 and 

 M 159 C. 



PODOPHTHALMUS (?), species 



Plate 4, Figure 2 



Description. — One specimen shows a portion of a carapace and 

 the general outline of the left half ; also the basal portion of the left 

 eyestalk. Estimated length of carapace 22, estimated width 51 mm. 

 Orbital margin very oblique, edge blunt; surface of orbit showing 

 in front of it, in dorsal view. Lateral margin of carapace very 

 sinuous, surface steeply inclined above the postlateral sinus, much 

 as in P. vigil (Fabricius), a Recent and Pleistocene form. Carapace 

 very incomplete and much broken. 



