112 BULLETIN 138, UNITED STATES NATIONAL MUSEUM 



CALLIANASSA KNAPPTONENSIS. new species 



Plate 38, fig. 4 



Propodus of major cheliped. — Outer surface only is exposed. 

 Manus very convex in a vertical direction, more so in the upper half 

 where it curves over almost horizontally. Proximal margin slightly 

 oblique to the upper and lower margins and rounded broadly into 

 them ; lower margin the less produced proximally, nearly horizontal, 

 but slightly sinuous, making a slight bay under the distal half of the 

 palm, and again curving obliquely upward from the base to the tip 

 of the finger ; upper margin of manus slightly convex, the distal half 

 sloping considerably downward, so that the manus is lower at the 

 distal end than elsewhere. (See measurements.) The lower mar- 

 gin forms a thin rim, widest at the proximal end, and marked with 

 a row of punctae just above the edge; upper margin less prominent, 

 with a few spaced tubercles. 



The lower half of the outer surface is partially tuberculate, the 

 tubercles concentrated in the distal lower corner, encroaching a little 

 on the finger while a few of the smallest ones reach down to the 

 marginal punctae. There are about 15 of the larger tubercles; the 

 five uppermost ones are in a nearly horizontal row, beginning below 

 the middle of the manus near its distal margin and ending at the 

 proximal third. 



The propodal finger occupies less than a third of the distal end of 

 the manus, its occludent margin is concave and entire. Above its 

 base a small, conical, sharp tooth projects from the manus distad into 

 the interdigital gap. Dactylus not preserved. The articulating 

 condyle of the manus lies half way between the upper margin and 

 the base of the tooth in the gap. 



Paratype. — Smaller than holotype, finger incomplete, surface im- 

 perfect. Agrees with the description of the holotype. 



Measurements. — Holotype, right and larger propodus, length from 

 proximal end above lower margin to upper proximal end of finger 

 19.4 mm., total length measured to tip of finger 26.5 mm., greatest 

 height 16.3 mm., least height, just behind fingers 15 mm, Paratype, 

 right manus, length from proximal end above lower margin to upper 

 proximal end of finger 16.4 mm., greatest height 12.6 mm., least 

 height, just behind finger 11 mm. 



Occurrence. — ^Washington: North bank Columbia River, three- 

 quarters mile northeast of Knappton; Oligocene series; two speci- 

 mens of major right manus, one with its propodal finger (holotype), 

 both embedded in nodules. Holotype in California Academy of 

 Sciences. 



