GEOLOGY AND PALEONTOLOGY OF THE, CANAL ZONE. 143 



Paratype (a). Cat No. 324287. U.S.XJL On a small piece of 

 crumbling rock there is an impression of the distal half of a finger, 

 but not the finger of the holotype. The impression has a similar 

 curvature and 3 rows of punctae are present. 



Paratype (6). Cat No. 324288, U.S.NJL Moin Hill, Costa Rica ; 

 third fossiliferous zone below the uppermost : just below level of rails 

 in railway cut Probably equivalent to Gatun formation. Oligccene 

 period. D. F. MacDonald, 1911. Station 5884J. A right propodus 

 without finger, similar in size to the holotype and corresponding in 

 its characters. 



CALLIAXASSA SPIKULOSA, mew specie*. 



Plate GL figs. 6-9. 



Callianassa cotti Pttsarr (part), Proc. Acad. Xat. ScL Phila., voL 64, 1913, 

 p. 503 (not pL 22, figs. 1-3). 



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

 lard Cut From lowest fossiliferous bed, third bed below lowest 

 limestone beds separated by rows of nodules. Lower part of upper 

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

 T. W. Yaughan, collectors. 191L Station 6020o. 



Holotype. Cat No. 324272, U.S.X3L Left propodus which was 

 encased in a nodule ; the manus has been removed except the proximal 

 part of the outer surface; of the propodal finger only the impression 

 remains. Length of manus less than greatest height; the upper and 

 lower margins converge distally, the upper margin convex, the lower 

 sinuous. Outer surface very convex in a vertical direction, having 

 a few scattered granules, also a short vertical line of 3 granules near 

 the upper distal corner, a row of 6 distant granules just above the 

 lower margin, and a sharp grannie near the sinus. The lower margin 

 is very thin and serrated: between the serrations are the truncated 

 bases of movable spines; 9 such spines remain. Upper edge bluntly 

 margined. Inner surface convex except near the inferior and distal 

 margins : a row of 3 granules on the middle line. 2 above the base of 

 the propodus, 2 parallel to the lower margin, and many small granules 

 just above that margin. An obliquely longitudinal line of pits below 

 the upper margin. 



The propodal finger is very much smaller than the dactylus and 

 thin: a cross section near its base is somewhat diamond-shaped, the 

 impression of the thumb (viewed sideways) is subtriangular. end 

 curved upward : prehensile edge concave ; at its base in the sinus be- 

 tween the fingers there is a short but strong curved tooth; on both 

 outer and inner surfaces of the thumb, leading down from the palm, 

 there is an oblique ridge. 



Measurements. Length of propodus to end of finger (approx.), 

 22.4 mm. ; length of manus, measured on the inner side, to sinus, 14.7 



