GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 



Material. Eleven dactyls and three propodal digits of the right 

 chela, all detached. One of the dactyls is made a holotype. 



Measurements. Length of longest dactyl 9.2 mm., height 3 mm. ; 

 length of holotype 6.1 mm., height 2.3 mm. 



Holotype. I have chosen a small specimen for holotype because 

 it is the best preserved. The dactyl is rather slender for the major 

 chela of a Panopeid, but it has the general character of Panopeus 

 and its allies. The prehensile edge has 3 enlarged teeth, placed as 

 follows, beginning at the proximal end : 1 1., 2 s., 1 1., 3 s., 1 1., 7 s., tip. 

 The proximal tooth is of the customary backward-pointing type^ 

 and is of moderate size compared to the basal tooth of living Pan- 

 opeids. The second of the large teeth is of nearly the same size,. 

 more pointed, and directed downward ; the third large tooth is defin- 

 itely smaller than the others. The small teeth are unequal and shaF- 

 low. The longitudinal depression either side of the teeth is punc- 

 tate; there are 3 other punctate furrows, one external, one internal 

 and the other dorsal but nearer the outer side ; just within the proxi- 

 mal half of the dorsal furrow there is a marginal line of granules. 



Paratypes. The number of small teeth intervening between the 

 larger teeth of the prehensile edge vary as follows, beginning at the- 

 proximal end : 1-3, 4-6, 6-8. 



One can not be sure that the propodal digits referred here belong* 

 to the same species as the dactyli. They too have 3 large teeth, which 

 are subequal and are separated by small teeth as follows, beginning 

 with the proximal large tooth: 2, 4-5, 4-6. Proximal end broken 

 off in each case, but in one instance a small tooth is visible proximal 

 to the first large tooth. When an immovable finger is applied against 

 a movable finger of complementary size, the large teeth of the former 

 shut into the sinuses distal to the corresponding large teeth of the' 

 latter. There are 6 longitudinal punctate depressions on each pro- 

 podus, one adjacent to the teeth on either side, one external, one in- 

 ternal, and two inferior. 



PANOPEUS, species. 



Plate 66, figs. 8 and 9. 



Locality. From the four feet of dark, stratified tuff and clay 

 immediately overlying the lower limestone bed. Las Cascadas sec- 

 tion. Upper part of Culebra formation. Oligocene series. D. F. 

 MacDonald and T. W. Vaughan, collectors. 1911. Station 6019&. 

 Cat. No. 324254, U.S.N.M. 



Material. One dactylus of right cheliped, with proximal end in- 

 complete. Dactylus very broad at base in proportion to its length, 

 also unusually thick. Length, 9.2 mm.; width, 4.7 mm.; thickness, 

 3 mm. In outer view the upper margin is much curved, the surface 



