Cypselid^e.] 



OSTEOLOGIA AVIUM. 



[Cypseunje 



Pam. 2. CYPSELID53. 



Subfam. Cypselin^e. 



Cypselus, 111. 



Apus, Linn. 



Type of Cypselidse. 



Cranium with a large occipital protuberance ; mouth wide ; a deep excavation be- 

 tween the orbits, as among the Trochilidw, but it is not carried backwards farther than 

 the vertex ; the orbits large ; septum with a posterior foramen ; there is, however, every 

 indication that ossification was still going on. Palatine bones expanded anteriorly, then 

 contracted, and having a lateral spine on their external edges near their junction with 

 the interarticular bones, united for their whole length. Interarticular bones straight. 

 Foramen magnum large, rounded. 



Sternum very similar to that of the Trochilidw, but with the hinder margin nearly 

 straight, instead of rounded ; the anterior furnished with grooves for the articulation 

 with the coracoids. 



Pelvis as among the Trochilidw, but broader anteriorly. Ribs projecting far back- 

 wards, but not placed so obliquely as among the Trochilidw. 



Fureulum small, but much larger than among the Trochilidw, and united to the 

 anterior edge of the keel near the tip by a ligament ; coracoids of moderate size, not 

 much expanded at their junction with the sternum. Scapula long, slightly deflected near 

 the point. Wing bones similar to those of the Trochilidw. Leg bones also similar. 



Measurements. 



Tenths. 



Length of humerus 5 



Length of ulna 7 



Length of metacarpus 8 



Length of femur 7 



Length of tibia 11 



Length of metatarsus 4 



Length of sternum 11J 



Tenths. 

 Breadth of posterior margin of sternum 6^ 

 Breadth of anterior margin of sternum 3^ 



Depth of keel 5± 



Length of head 12 



Breadth of head 6 



Length of pelvis Hi 



Breadth of pelvis 9 



Illustrations. 

 Skeleton, sternum, pelvis, and metatarsi, Plate I. bis. 



Cypselus, III. 



Melba, Linn. 

 Similar to C. ajpus, only larger. In the British Museum. 



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