Larid^;.] 



OSTEOLOGIA AVIUM. 

 Illustrations. 



[Sterninje. 



Skeleton, Plate XI. L. 



Sternum, pelvis, palatine bones, and meta- 

 tarsi, Plate XXXVI. fig. 2. 



Larus, Linn. 



Marinus, Linn. 



Precisely similar to the preceding, but there is a variety in the outer fissure on the 

 right side being closed and converted into a foramen, and not on both sides. 

 I have also specimens of Larus cinerea and Argentatus, which are also similar. 



Sterna, Linn. 



Macroura, Naum. 

 Cranium similar to Larus. Palatine bones not so much sloped on their hinder 

 margins towards the interarticulars. 



Sternum similar to Larus, but shorter in proportion to its length, and the keel 

 deeper. 



Pelvis similar, but broader in proportion to its length. 



Furculum and Coracoids similar to Larus. 



Wing-bones. Ulna much longer than the humerus ; thumb reaching for about one- 

 third the length of the metacarpus. 



Leg-bones. Tibia not elongated beyond the femur, but flattened and bent down- 

 wards. 



Length of humerus 

 Length of ulna . . 

 Length of metacarpus 

 Length of femur . 

 Length of tibia . . 

 Length of metatarsus 

 Length of sternum 



Measurements. 



Tenths. 

 18 



22 

 11 



8 

 13| 



6 

 14 



Tenths. 



Breadth of posterior margin of sternum 7 \ 

 Breadth of anterior margin of sternum 6J 



Depth of keel 5J 



Length of head 24 



Breadth of head 7 



Length of pelvis 16 



Breadth of pelvis 9 



Sterna, Linn. 



Melanocephala. 

 This bird does not differ from the preceding. I have also a specimen from Australia, 

 which I believe to be Anous stolida, which differs from the other Terns in having 

 on each side of the hinder margin of the sternum one outer moderate-sized fissure, and 

 a very small foramen between it and the keel. 

 226 



