988 ON THE OSTBOLO&Y OF THE IMPENNES. [DcC. 13, 



EXPLANATION OF THE PLATES. 

 Plate LIX. 

 c.p.= cerebellar prominence, dome. ^.= palatine, 

 c.r. = coronal ridge. s.c. =sagittal crest. 



^.=lachryraal. S5'.p.r.=squaitioso-parietal ridge. 



?j. = nasal. <./.= temporal fossa. 



n. /)»ix.= nasal process of premaxilla. 



The Dorsal Aspect of the Skull. 

 Fig. 1. The skull of Spheniscus magellanicus Forst., to show the great size of 



the temporal fossa and of the squamoso-parietal wings ; the sagittal 



crest, coronal ridge, and the slight development of the supra-orbital 



ledge. 

 Fig. 2. The skull of Pygoscelis papua Forst., to show the great development 



of the supra-orbital ledge, the free nasal processes of the premasiUa, 



the form of the temporal fossa, and the lachrymal. 

 Fig. 3. The skull of Apfcnodytes patagonica Forst., to show the supra-orbital 



ledge, the free nasal processes of the nasal processes of the premaxilla, 



the shallow temporal fossa, and great width at the transverse lamb- 



doidal ridge. 

 Fig. 4. The skuU of Eudyptula alhosignata Finsch, showing the almost 



complete absence of a supra-orbital ledge and the form of the 



temporal fossa. 

 Fig. 5. The skull of Catarrhactes chrysocome Forst., to show the form of the 



supra-orbital ledge and of the temporal fossa. 



Plate LX. 



ff. = angulare. p.o.^.=postorbital process. 



a.o./).=antorbital plate. ^.^.=paroccipiial process. 



c.^.= cerebellar prominence, ^»ia;.= premaxilla. 



(:i.s.=dentary suture. ^i;.= pterygoid, 



i.o.s. =iuterorbital septum. 5=quadrate. 



Z.=lachrymal. v—^omev. 



y3.= palatine. 



The Lateral Aspect of the Skull. 



Fig. 1. The skull of Eudyptula alhosignata Finsch, to show the temporal 

 fossa, the slightly curved quadrato-jugal bar, and the dentary suture 

 of the mandible. 



Fig. 2. The skull of Catarrhactes chrysocome Forst., to show the temporal fossa, 

 the size of the squamoso-parietal wings, the great curvature of the 

 quadrato-jugal bar and of the dentary suture of the mandible. 



Fig. 3. The skull of Megadyptcs antipodum Homb. & Jacq., for comparison 

 with that of Catarrhactes, to show the greater size of the temporal fossa 

 and squamoso-parietal wings and the more slender jaws. 



Plate LXI. 



Additional letters. 



a?s. =ali8phenoid. ;.=jugal. 



avg. = angulare. max. = maxilla. 



ar. — articulare. mes. = mesethmoid. 

 ant.b.f. = anterior basicranial fontanelle. op. = opisthotic. 



ft.oe.=basioccipital. p. = parietal. 



ht.pl. = basi temporal plate. ^jar. = parasphenoid. 



h.s. = basisphenoid. pro. = prootic. 



co>'. =coronoid. s.a. = supra-angular. 



d. = dentary. «.o. = supra-occipital, 



ep.o. =epiotic. s^.=8plenial. 



f.r. = exoccipital. sg'.= squamosal, 



./r. = frontal. v. = vomer. 

 A.p)". = hemipterygoid. 



The Skull of the Nestling. 

 Fig. 1. Inner view of a longitudinal section of the skull of a nestling Catarrhactes 

 chrysocone, showing the unclosed sutures. 



J 



