GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 137 



A 2 . Manus and carpus meeting in a vertical line — Continued. 



B 2 . Lower margin of manus directed straight forward or nearly so ; that is, 

 at right angles to its proximal margin. 

 C 1 . Upper margin of manus subparallel to lower margin. No tooth in 

 sinus between fingers. Carpus much higher than long. 



D 1 . Lower margin serrulate qu a drata, p. 145 



D 2 . Lower margin granulate toulai, p. 146 



C 2 . Upper margin of manus directed forward and downward toward lower 

 margin. 

 D\ A large tooth in sinus between fingers and situated on base of im- 

 movable finger abbreviata, p. 147 



D 2 . A small tooth in sinus between fingers, and situated near movable 



finger. Carpus very little, if at all, higher than long hilli, p. 148 



D 3 . No tooth in sinus between fingers. Fingers long and strong. 



vaughani, p. 148 

 B 3 . Lower margin of manus unknown. A stridulating ridge near the hori- 

 zontal upper margin stridens, p. 151 



A 3 . Meeting of manus and carpus unknown. 



B\ Immovable finger slender. Distal articulating edge of manus crenulate 



and very oblique crassimana,^. 141 



B 2 . Only the dactylus known. 



C\ Dactylus of large size. Cross section at base subcylindrical. Pre- 

 hensile edge thin magna, p. 151 



C 2 . Dactylus half as long as preceding, more compressed. Prehensile 

 edge thicker crassa, p. 152 



The 2 Callianassas to which specific names are not given are ex- 

 cluded from the above kej^. 



CALLIANASSA OVALIS, new species. 



Plate 59, figs. 1-4. 



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. Vaughan, collectors. 1911. Station 6020&. Holotype 

 and one paratype. Cat. No. 324269, U.S.N.M. 



Holotype. — A left chela with wrist and arm attached, and enclosed 

 in a nodule which is split in two. The specimen had been crushed, 

 and the half nodule containing the impression shows also small 

 pieces of the cheliped itself. Wrist and manus together oblong- 

 oval ; line between them oblique ; upper and lower margins of manus 

 slightly convex; greatest width about equal to the upper length; 

 from the widest point, the lower margin of the propodus slants 

 upward. Fingers directed straight forward and of subequal length. 

 Immovable finger an isosceles triangle, the base of which is two- 

 thirds as long as either side ; end blunt ; cutting edge with a shallow 

 triangular tooth at the proximal two-fifths. Movable finger sub- 

 oblong, end broad, cutting edge with a broad, shallow, rounded tooth 



