14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I39 



p. 195). Other peculiarities have been described in the musculature. 

 The sum of these characters justifies treatment of the Rynchopidae 

 as a distinct family in their suborder. 



The fossil humerus, type of Mancalla calif 'orniensis Lucas, that 

 was the first intimation of a flightless auk on the west coast, while 

 unique for many years, now has been supplemented by abundant ma- 

 terial from which an additional, smaller species, Mancalla diegense 

 (L. H. Miller), is recognized. It has been possible also to construct 

 a composite skeleton of the larger one that is sufficiently complete 

 to give a clear picture of its form and characters. The evident peculiari- 

 ties of the genus Mancalla are found in the wing, as elsewhere the 

 skeleton resembles that of other alcids, except for differences of a 

 generic and specific nature. In comparison of the wing with that of the 

 great auk, now extinct, that formerly ranged the coasts of the North 

 Atlantic, the humerus of Mancalla is generally similar, the forearm 

 appears proportionately shorter, and the hand more elongated. Ulna, 

 radius, metacarpal, and phalanges so far as present are more slender. 

 The head of the humerus in Mancalla differs decidedly in the relative 

 angles of different elements, and also in the conformation of the 

 distal articular surface. The general indication in the west-coast bird 

 is of a proportionately longer wing, with the slighter bones to be ex- 

 pected in a form of lesser bulk. Loye Miller (1946, pp. 34-36) and 

 Loye Miller and Howard (1949, pp. 222, 225) have likened the 

 specialization seen in the wing to that found in penguins and explain 

 any similarity to the great auk, Pinguinis impennis, as due to con- 

 vergence. On this basis they have separated Mancalla from the other 

 auks in the family Mancallidae. While I followed this, with some 

 reservation, in the last revision of the fossil list (Wetmore, 1956, pp. 

 3, 80-81), a further review of the subject raises definite doubt, since, 

 except for some specialization in the wing, Mancalla, as said above, 

 is like other alcids. The change in the wing is no greater than that of 

 Pinguinis, though the divergence is in a different direction. It would 

 seem sufficient to place Mancalla in a well-marked subfamily, rather 

 than in a separate family. 



Finally, the proposals of several authors to separate the auks in a 

 distinct order appear to require further study. 



Strigiformes. — Old World ornithologists in the main regard the 

 owls as belonging to a single family, but while all are deceivingly 

 similar in general aspect, Ridgway (1914, p. 598) years ago sum- 

 marized the considerable structural characters that separate the 

 Tytonidae and the Strigidae. It is necessary here only to point out the 

 more outstanding differences of the barn owls in lack of the manu- 



