52 Prof, a a Marsh— On Birds ivith Teeth 



distal end of the tibia has on its anterior face no ossified supraten- 

 dinal bridge, differing in this respect from nearly all known aquatic 

 birds. The fibula is well developed, and resembles that of the 

 Divers. The patella is large, as in Podieeps, and in position extends 

 far above the elevated rotular process of the tibia. 



The tarso-metatarsal bone is much compressed transversely, and 

 resembles in its main features that of Colymhus. On its anterior face 

 there is a deep groove between the third and fourth metatarsal 

 elements, bounded on its outer margin by a prominent rounded 

 ridge, which expands distally into the free articular end of the 

 fourth metatarsal. This extremity projects far beyond the other two, 

 and is double the size of either, thus showing a marked difference 

 from Rnj known recent or fossil bird. There is a shallow groove, 

 also, between the second and third metatarsals. The second meta- 

 tarsal is much shorter than the third or fourth, and its trochlear end 

 resembles in shape and size that of the former. The existence of a 

 hallux is indicated by an elongated oval indentation on the inner 

 margin above the articular face of the second metatarsal. The free 

 extremities of the metatarsals have the same oblique arrangement 

 as in the ColymhidcB, to facilitate the forward stroke of the foot 

 through the water. There are no canals or even grooves for tendons 

 on the posterior face of the proximal end, as in the Divers and most 

 other birds ; but below this, there is a broad, shallow depression, 

 extending rather more than half way to the distal extremity. 



The phalanges are shorter than in most swimming birds. Those 

 of the large, external toe are very peculiar, although an approach 

 to the same structure is seen in the genus Podieeps. On the outer, 

 inferior margin, they are all deeply excavated. The first, second, 

 and third have, at their distal ends, a single, oblique, articular face 

 on the inner half of the extremity, and the outer portion is produced 

 into an elongated, obtuse process, which fits into a corresponding 

 cavity in the adjoining phalanx. This peculiar articulation prevents 

 flexion except in one direction, and greatly increases the strength 

 of the joints. The terminal phalanx of this toe was much com- 

 pressed. The third, or middle, toe was greatly inferior to the fourth 

 in size, and had slender, compressed phalanges, which correspond 

 essentially in their main features with those of modern Divers. 



The remains preserved of Hesperornis regalis show that this 

 species was larger than any known aquatic bird. All the si3ecimens 

 discovered are in the Yale College Museum, and agree essentially 

 in size, the length from the apex of the bill to the end of the toes 

 being between five and six feet. The habits of this gigantic bird 

 are clearly indicated in the skeleton, almost every part of which has 

 now been found. The rudimentary wings prove that flight was 

 impossible, while the powerful swimming legs and feet were 

 peculiarly adapted to rapid motion through the water. The tail 

 appears to have been much expanded horizontally, as in the Beaver, 

 and doubtless was an efficient aid in diving, perhajDS compensating 

 in part for want of wings, which the Penguins use with so much 

 effect in swimming under water. That Jlesperornis was carnivorous 

 is clearly proven by its teeth ; and its food was probably fishes. 



