GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 133 



there is some intercostal granulation. Prehensile edge armed with 

 fine teeth and divided into 3 sinuses separated by 2 large teeth; the 

 distal of these has its distal edge normal and its proximal edge 

 oblique to the margin of the dactylus ; the top of the other large tooth 

 is broken off; the terminal bay has a somewhat enlarged, but still 

 small, tooth at its middle. 



Paraty-pes. — (a) Distal half of dactylus, but with small tip lack- 

 ing, same width as holotype; terminal sinus same length but more 

 curved, so that the distal border of the boundary tooth is shorter; 

 middle sinus half as long, nondentate, next boundary tooth broader 

 than in holotype. 



(b) Dactylus with proximal end lacking, same width as holotype, 

 costae more rounded, terminal sinus a little shorter, boundary tooth 

 with end missing, enlarged middle tooth better developed than in 

 holotype, pointing obliquely distad; middle sinus longer, boundary 

 tooth broken. 



(c) Propodal (?) finger broader than the others, showing one 

 sinus nearly equal to 2 sinuses of the holotype and limited by a large 

 tooth with nearly equal sides. 



I have placed this species in Kephrops on account of the ribbed 

 fingers irregularly toothed. The variations in the dactyl may repre- 

 sent either individual or sexual variation. 



NEPHROPS, species. 



Plate 57, fig^. 25 and 26. 



Locality. — Panama Canal Zone. From near Mount Hope in ditch 

 through swampy ground. About one- quarter mile from present sea 

 beach, 6 to 8 feet above high tide. Pleistocene series. D. F. Mac- 

 Donald, collector. April, 1911. Station 5850. Cat. No. 324249. 

 U.S.N.M. 



Material. — Dactylus of right cheliped, 12 mm. long; distal half 

 moderately curved toward the propodal finger, but the whole finger 

 strongly curved downward; 6 strong, longitudinal costae, 3 dorsal, 

 1 marginal, 2 ventral; about 9 lines of punctae; the prehensile teeth, 

 36 in all, are larger and more projecting in that two-fifths of the 

 margin just posterior to the middle. 



After the above description was written the proximal half of the 

 specimen was accidentally crushed and destroyed. 



Although the dactylus is much more curved than in any species of 

 Nephrops, yet its ornamentation is so similar to that of the preced- 

 ing species, N. costaius, that it is referred to the same genus. 



