1046 ON THE OSTEOLOGY OF THE PYGOPODES. [DeC. 19. 



jn'o. = prodt\c. soJ. = supraorbital ledge. 



^j^.=pterygoid. si^.^sqiiatiioBal. 



§'. = quadrate. £5.^. = squamosal prominence. 



s.o'.= supra-angular. .'!g.;ow. = squamoso- parietal wing. 



s.c. = sagittal crest. ^.f.=: temporal fossa. 



5.o.=supraoccipital. i;r.*^.= trigeminal foramen. 



so.ff. = supraorbital groove. v. = vomer. 



Fig. 1. Dorsal aspect of the skull of Podicijjes cristatics (jd. 1020), to show the 



well-developed sagittal crest, temporal fossge, coronal ridge, squamoso- 



parietal rings, the free lachrymal, and the feeble supraorbital grooves. 

 Fig. 2. Dorsal aspect of the skull of Colymhus septentrioimlis (p. 1020), to 



contrast with fig. 1, with the great development of the supraorbital 



grooves and ridges and the lachrymal fontanelle. 

 Fig. 3. Lateral aspect of fig. 2 (p. 1021), showing the conspicuous cerebellar 



prominence, temporal fossa, and supraorbital ledge. 

 Fig. 4. Lateral aspect of the skuU of a nestling Podicipes criatatus, outer view 



(p. 1030), to show the unclosed sutures. 

 Fig. 5. Lateral aspect of the skull of a nestling Podicipes cristatus, inner view, 



to show the unclosed sutures. 

 Fig. 6. Ventral view of skull of an adult Colymhus septentrionalis (p. 1026), to 



show the schizognathous palate. 

 Fig. 7. Lateral aspect of a portion of the pterygoid and palatine of Colymbus 

 glacialis (p. 1032), to show the hemipterygoid. 



