108 BULLETIN 138, UNITED STATES NATIONAL MUSEUM 



late. Fixed finger (from cast) nearly as long as the hand, not 

 toothed, very slightly curved on its inner edge. Movable jfinger un- 

 known. Surface irregularly and minutely wrinkled, and marked 

 along the upper edge by a row of about seven foramina, surrounded 

 by a raised lip looking forward, and over the rest of the surface by 

 a number of pustules, which are largest and most closely placed on 

 the upper half" (Gabb). 



It is impossible to determine the status of this species without 

 seeing the specimens figured by Gabb. These are apparently not 

 extant. A lot of five specimens collected by Gabb and labeled 

 ''Callianassa> stimpsoniV has been loaned to the writer by the 

 Philadelphia Academy of Natural Sciences through Dr. H. A. Pils- 

 bry. It bears the labels " Clayton " and '« Martinez." None of the 

 five answers to the description or figures of O. stimpsonii,- two (wrist 

 and hand) represent another species of Callianassa., two are crab 

 claws, while the fifth is the carapace of an undetermined shrimp. 



CALLIANASSA INCERTA, new species 

 Plate 25, figs. 1-J 



Among the specimens borrowed from the Academy of Natural 

 Sciences, Philadelphia, under the name, CalVmnmsa stimpsonii Gabb 

 are two specimens of CaUiaimssa of a different species; they are' 

 labeled " Martinez " and " Clayton,"'and are Eocene. Right manus, 

 holotype, and left carpus or wrist, paratype. 



Description.— M^nus: Proximal margin concave, upper margin 

 convex, lower straight except where it curves upward at the proxi- 

 mal end (pi. 25, fig. 1). Outer surface very convex in a vertical 

 direction, inner surface slightly convex, upper and lower margins 

 thin, edge acute (pi. 25, fig. 3). The cavity for insertion of dactylus 

 equals half the height of distal end of manus and meets the stump 

 of propodal finger. This is thin, prehensile edge sharp, bearing a 

 broad triangular tooth; inner surface (pi. 25, fig. 2) divided by a 

 longitudinally oblique ridge into two surfaces the upper of which is 

 concave. Outer layer of shell lacking, exposed layer covered with 

 low transverse reticulations; upper distal corner of outer surface 

 slightly roughened with oblong granules. 



Carpus (pi. 25, fig. 4) : Embedded in rock. Like the hand, very 

 convex externally, upper and lower margins turned strongly inward 

 .Surface nearly smooth, with indications of oblong granules on the 

 middle third of the lower half. 



Measurements.~l.engih of manus to suture 8.5 mm., greatest 

 height near proximal end 9 mm., distal height 7.5 mm. Length of 

 wrist 6.5 mm., height T.3 mm. 



