INSECTIVORA OF THE SANTA CRUZ BEDS. 375 



ingly small, but may, nevertheless, have supported a well developed 

 digit. 



The magnum is considerably larger than the trapezoid and in shape 

 resembles that of Chrysochloris more than do the other carpals. Proxi- 

 mally it is covered almost entirely by the lunar, but also sends out a short 

 process to reach the scaphoid. Distally, it supports only the third meta- 

 carpal and appears to have no connection with the second. The unciform 

 is relatively very small, especially in the proximo-distal diameter, which 

 gives it a flattened, almost scale-like appearance ; evidently, it is beginning 

 to undergo a marked reduction. 



In Chrysochloris the carpus has experienced an extraordinary degree of 

 modification and reduction ; the central is suppressed, as are also the 

 trapezium and trapezoid, the second metacarpal articulating directly with 

 the scaphoid. There are thus only two bones in the distal row of the car- 

 pus, the magnum and the unciform, and of these the unciform is much 

 reduced, as is also the pyramidal. 



The number of metacarpals present in Necrolestes was probably five, 

 though only two, the third and fourth, are preserved in connection with 

 the carpus. From the size of the trapezium, trapezoid, and unciform it 

 may be inferred that the metacarpals did not differ greatly in size and 

 that there was no such enlargement of me. Ill at the expense of the others 

 as has taken place in Chrysochloris. The third metacarpal is short and 

 stout, but not nearly so broad as in the African genus, and it entirely 

 lacks the relatively great extension toward the external side which in the 

 latter reaches to the ulna. The proximal end bears a saddle-shaped sur- 

 face for the magnum and the distal end has a nearly plane, very slightly 

 saddle-shaped facet, which is very oblique to the axis of the shaft, sloping 

 downward and forward. This distal end is very different from that seen in 

 Chrysochloris, which is modelled for articulation with the great ungual and 

 looks as if the first phalanx (if not the second also) were ankylosed with it. 

 The fourth metacarpal is but little smaller than III, which it resembles in 

 shape; it articulates with the unciform and is not, as in Chrysochloris, 

 received into a depression beneath the great ulnar projection of me. III. 



In Chrysochloris the metacarpus is exceedingly peculiar ; me. I is very 

 small and is attached to II ; the latter is larger, though very slender, and 

 is carried by the scaphoid ; me. Ill is relatively very large, while me. IV 

 is very much smaller and is carried by me. Ill, while me. V is wanting. 



