178 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



stone beds separated by rows of nodules. Lower part of upper half 

 of Culebra formation. Oligocene series. D. F. MacDonald and 

 T. W. Vaughan, collectors. 1911. Station 6020a. Cat. No. 324294, 

 U.S.N.M. 



Material. A specimen 9.3 mm. long and 7.7 mm. wide, which re- 

 sembles the proximal part of the right manus of a crab. The outer and 

 lower surfaces are exposed, but the outer layer of shell has almost dis- 

 appeared. The surface gradually ascends to a line a little below the 

 middle where a blunt longitudinal ridge is formed. Just below the 

 upper margin, and also just within the lower margin on the inner 

 side, there is a narrow furrow. 



The blunt crest is suggestive of the Portunidae. 



BRACHYRHYNCHA, family, genus, and species indeterminable. 

 Plate 64, fig. 5. 



Locality. Panama Canal Zone. Las Cascadas section, Gaillarcl 

 Cut. From lowest fossiliferous bed. Third bed below lowest lime- 

 stone beds separated by rows of nodules. Lower part of upper half 

 of Culebra formation. Oligocene series. D. F. MacDonald and 

 T. W. Vaughan, collectors. 1911. Station 6020a. Cat. No. 324258. 

 U.S.N.M. 



Material. Two specimens, each embedded in a nodule, of a frag- 

 ment which appears to be the merus segment of an ambulatory leg 

 of a crab. The surface is flat, the lateral margins are arcuate and 

 there is a shallow longitudinal depression near one edge. The shape 

 is very suggestive of the Portunidae and yet they do not closely 

 resemble any known species. 



Superfamily OXYRHYNCHA. 

 Family PARTHENOPIDAE. 



PARTHENOPE PANAMENSIS, new species. 



Plate 66, figs. 10 and 11. 



Type-locality. Panama Canal Zone. Las Cascadas section. 

 From fifth or topmost limestone. Emperador limestone. Oligocene 

 series. D. F. MacDonald and T. W. Vaughan, collectors. 1911. 

 Station 6019^. Cat. No. 324257, U.S.N.M. 



Measurements. Length of arm measured along lower margin (in- 

 complete), 24.6 mm.; distal width, measured on inner, lower surface. 

 6.6 mm. ; minimum width, on the same surface, 4.7 mm. 



Holotype. One specimen represented by only the merus joint of 

 the left cheliped. This segment is thick; a cross section is quadri- 



