NO. 1320. NO TES ON FOSSIL BIR DS—L UCAS. 553 



BAPTORNIS ADVENUS. 



The skull of this bird is still unknown, so that we do not know posi- 

 tively whether or not it had teeth, although this is probably the case. 

 Neither do we know the relationship between Baptornis and Hesper- 

 ornis; both were rtightless aquatic birds, but the structure of the limbs 

 shows that at least they l)elono- in separate families. 



The body appears to haw been stout, the neck long- and slender, the 

 indi\'idual vertebra^ being nuich more elongate than in Hesperornis, 

 approaching in this respect Plotus or Podiceps. 



The vertebra? present, unfortunately, are not consecutive, a portion 

 onlv of the cervicals being present, while some of the dorsals belong 

 to the anterior portion of the series and others to the posterior part. 

 The hypapophyses appear to have been developed, much as in Hesper- 

 ornis, well forward in the dorsal region, in contrast to what occurs in 

 modern water birds, such as penguins, auks, and loons, in which the 

 hypapophyses begin immediately in advance of the sacrum and are 

 longest about the middle of the series. 



This would throw the center of effort farther forward in the old 

 diving birds than in modern species, and may be due to the use of 

 the luuscles either while capturing fish or in moving about on land. 



The synsacrum seems to have comprised ten vertebra^, but this is 

 not certain, the first of which belongs to the dorsal series and bore a 

 ri!). The sacrum of Hesperornis contained fourteen vertebra. Noth- 

 ing of the pelvis is present save the anterior portion of an ilium, and 

 this, although weathered, resembles the corresponding portion of the 

 ilium of Hesperornis. The dorsal vertebrse were all free, and so were 

 the ossa innominata in both Baptornis and Hesperornis, but this free- 

 dom is to be regarded as due to the aquatic habits of these birds and 

 not as morphological characters. While the bones of aquatic animals 

 are heavier than are those of land animals, ossification and union 

 between contiguous parts takes place much more slowly, and in such 

 strictly aquatic birds as the penguin and great auk the dorsal vertebrae 

 and ossa innominata are similarly free. 



The coracoid is rather wide and thin, much longer than that of 

 Hesperornis, and apparently without a precoracoid process or perfo- 

 ration; an articulation is present for the reception of the clavicle, but 

 this latter bone was not preserved. 



Only the proximal portion of one scapula, the left, is present; this 

 indicates a stout lione, and there is a suggestion that it may have 

 expanded distally, as in penguins, but this is suggested, nothing 

 more. 



The humerus is short, round in section, and considerably curved, as 

 in Apteryx. Although the proximal end is lacking, it seems to have 

 been not far from 4 inches (100 mm.) long. The radius and ulna are 

 extremely short, measuring but three-fourths inch (20 mm.) in length. 



