TERTIARY DECAPOD CRUSTACEANS. 171 



slender; no spine visible on outer or posterior margin, but there is a transverse 

 depression, which may indicate a tooth further down, in the matrix. The 

 carpus is short and squarish; spine not visible. The propodus has a very con- 

 vex lower margin; the manus is costate, having 3 blunt costae on the outer 

 surface ; the middle one is the most prominent, straight, and directed toward 

 the middle of the interdigital sinus, but stops short of it; the upper costa 

 begins at the tooth at the articulation with the carpus, is slightly concave 

 upward, and ends in a distally projecting lobe just above a large protuberance 

 at the lateral articulation with the dactylus; the lower costa begins proximally 

 near the middle costa, from which it gradually diverges and fades out near the 

 middle of the immovable finger. A spine on inner surface near distal end, at 

 least in major chela. On either side of the manus at its articulation with the 

 dactylus there is a large, smooth, rounded protuberance, which is bounded 

 proximally by a deep, narrow furrow; below this protuberance and distal to it 

 there is, on the outer surface at least, a thick, subacute lobe, overlapping the 

 dactylus. The prehensile teeth are very unequal, smoothly rounded, dark- 

 colored; in the larger chela the basal tooth of the dactylus is very large and 

 directed obliquely backward, and the fingers gape moderately. 



Only the basal half of the first 3 ambulatory legs is present. The 

 sternum and abdomen are visible, the latter being oblong-triangular 

 and unusually wide for a male; the third, fourth, and fifth segments 

 are fused; the sixth has rapidly converging sides; the seventh is wider 

 than long. 



Paratype. Portion of a right cheliped, comprising the carpus, 

 manus, and a small basal piece of each finger. Cat. No. 2258, Mus. 

 Phila. Acad. Nat. Sci. 



Measurements. Length of manus above, excluding spine, 33 mm., 

 length at middle of outer surface 44 mm., height of manus to base of 

 superior spine 34 mm. 



The following is a description of the paratype: 



This cheliped shows some features better than the holotype. The carpus 

 has 4 nearly equal sides ; the inner spine is visible, though broken off near its 

 base; also a cross-section of a smaller spine at the distal outer angle which is 

 broken off quite at the base; there is a longitudinal obtuse ridge on the proxi- 

 mal half of the segment terminating bluntly not far from the middle; if con- 

 tinued, it would cross the distal upper angle. 



The manus is much flattened on the inside. At the distal end of the inner 

 upper margin there is a spine pointing distad and a little upward and inward ; 

 its tip is broken off. Costae of outer surface much lower and flatter than in 

 the holotype; the upper costa fades out altogether proximally. The large 

 lobe at the articulation with the dactylus is broken away, but the lobe below 

 it is large and projects distally well over the dactylus. On the inner surface 

 of the manus, half-way up and at one-fifth the distance behind the distal end, 

 there is a slender spine (with tip broken off) pointing inward and slightly 

 distad. A similar spine has been partially uncovered on the major chela of 

 the holotype. The dactylus has one large, low, dark-colored molariform 

 prehensile tooth at its base (which shows that the cheliped is the minor one 

 of the pair), and on the inner side a small crescentic, blackish, articulating 

 knob. The corresponding protuberance on the manus has been broken off. 



