LaRrip&. | OSTEOLOGIA AVIUM, [ STERCORARINAE. 
STERCORARIUS, Briss. 
Pomarinus, Temm. 
Cranium rather flattened. Orbits large; a moderate-sized foramen in the centre, 
and a smaller one above it; a deep depression over each orbit. Palatine bones narrow, 
bending downward at the lateral edges; wider than in Chroicocephalus ridibundus. 
Interanticular bones bending inwards at their hinder ends, flattened. 
Sternum with a large and deep fissure on each side of the kéel, which is very deep 
and much curved on its inferior edge; much scolloped out on its anterior edge. 
Manubrial process small, laterally compressed, pointed. 
Pelvis long; the pubis and ischium very much prolonged backwards. Obturator 
- foramen long, narrow. Ischiadic foramen small; the division of the sacral vertebrae 
apparent. 
Ribs moderate; styliform processes long, pointing upwards. 
Furculum flattened, no projection at the junction of the rami. 
Coracoids very strong, flattened on the upper side. 
Scapule thick, of nearly the same width throughout, pointed at their extremities. 
Wing bones very long, especially the metacarpal. 
Leg bones light. 
Measurements. 
Tenths. Tenths, 
Henothofiumerus . 2 . . . 4602 Breadth of anterior . . . . . 
entotheomulnar, 4 <9 2 ah 2tis5 47 MAT SIMeOtCitOn , wee a sea ae ko 
Length of metacarpus . . . . 42 Depiinomkec ea srr a 6S 
ensthivortemur # . 4 . 5 . £8 Ibenen cr ineecl | As BB ae wok 
Renetieottioias. » = . . 4 » 26 breads Omneade aoa. 8 a 2 CS 
Length of metatarsus. . . . . 22 enesth ofpelvis . . § » » . 39 
lhength of sternum . .., . . 380 Breadthvot pelvis » = - . «. » 19 
Breadth of posterior margin. . . 18 
Illustrations, 
Sup. 2, pl. 10. Details, pl. 10, I. 
The genus stercorarius differ from the genus larus, in having only one fissure on the 
posterior margin of the sternum, in the more depressed form of the cranium. 
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