339 
PAL.EOSYOPS LEIDY, AND ITS ALLIES. 
and more irregular at its extremity. The sigmoid cavity is damaged in this speci- 
men. It was broader and not as high as in Lymnohyops . The radial face of the 
ulna is concave from side to side and much broader, the oblique ridge upon its upper 
portion being more marked than in L. laticeps. The shaft of this ulna is broader, 
flatter and more angular than in the last named form. The relations of the 
distal extremity are about the same as in L. laticeps, this part being exca- 
vated upon its internal border and more set oft from the shaft than in the 
latter. The facets of the distal extremity are the same in size as in L. 
laticeps. From the size and position of the bones of the lower arm of P. longi- 
rostris we may conclude that this species had a shorter and heavier anterior 
extremity than L. laticeps. This is farther shown in the size and form of the 
manus. 
Manus . — The material relating to the manus is as follows : a right meta- 
carpal II and IV found associated with jaw No. 10,275, and radius and ulna of 
the same number. In addition to the above material I have found a lunar 
and magnum which I refer to this species. 
Lunar . — The lunar closely resembles that of P. paludosus in its general form 
and the position of its facets, although it dift’ers from the latter in being much 
smaller. The general proportions of the lunar are broad and low ; its vertical axis 
exceeding somewhat the transverse. The depth of this lunar is short compared 
with its other dimensions. The posterior part ol the superior facet is much lower 
than the anterior, being strikingly so as compared with P. paludosus. The lunar- 
magnum facet is larger proportionately than that ol the larger species and 
approaches nearer the median axis of the bone. The lunar-unciform is very large 
but not as deeply concave and more obliquely placed than in P. paludosus . The 
lunar in this species also resembles that of the largest species in having only a 
slight prolongation of its inferior face between the magnum and unciform. 
Magnum . — The form of the magnum is rectangular; its transverse axis 
only slightly exceeds its vertical. The magnum-lunar facet is more nearly vertical 
than in P. paludosus, and the anterior part of the superior face is more hori- 
zontal, with the pivot less ascending than in the latter. The magnum-metacarpal III 
facet is deeply concave and not overhung by a beak-like process as in P. paludosus. 
Metacarpals. — The second metacarpal is in a good state of preservation ; it is 
much shorter than that of P. paludosus but proportionately broad in comparison with 
its length. Its distal extremity is broad and heavy. The facets of the proximal 
end are the same as in P. paludosus, the superior one being not so concave as in the 
latter. Unfortunately the projecting portion of this metacarpal which articulates 
with the magnum is broken, but otherwise the shape of the proximal extremity 
closely reseinbles that of the larger species of this genus. Only the proximal part 
of metacarpal IV is preserved. It is quite massive and the facet of its superior face 
rather more oblique than in P. paludosus. Its radial facets are unusually large for 
46 JOITK. .4. N. S. PHILA., VOL. XI. 
