REPORT ON THE SPHENISCIDiE. 5 



Spheniscus and that of Eudyptes, being more rounded tlian in the former and less so 

 than in the latter. 



A large transverse osseous crest is developed to a greater or less extent in the 

 temporal region of every Penguin. This crest is formed by the squamosal, parietal, and 

 occipital bones. In every species it makes its appearance immediately above the external 

 auditory aperture, and extends vertically upwards towards the vertex of the skull. Its 

 relation to the latter, however, varies in different genera. In Euchjptes it terminates 

 above, opposite the base of the post-orbital process, by coalescing with the posterior 

 surface of the cerebral prominence of the skull, and consequently falls short of the cranial 

 vertex. In Spheniscus, on the other hand, the temporal crest is developed to a greater 

 extent than in Euchjptes, and instead of subsiding opposite the base of the post-orbital 

 process ascends to the vertex of the skull, where it meets its fellow of the opposite side. 

 In Spheniscus, moreover, unlike Eudyptes, the temporal crest lies altogether behind the 

 cerebral prominence, and coalesces above with the upper part of the cerebellar portion 

 of the skull. In Eudyptes the temporal crest forms the posterior boundary of a narrow 

 groove, which is limited to the lower hcdf of the lateral surface of the cranium, while in 

 Spheniscus this groove is much wider and extends from the base to the vertex of the 

 skull. In Spheniscus mendiculus and Spheniscus minor the temporal crest differs 

 somewhat from that of other species of the genus, and presents a condition intermediate 

 between that which is characteristic of Sp)hemscus and that met with in Eudyptes. In 

 Spheniscus mendiculus the temporal crest scarcely reaches the vertex of the skull but 

 as in Spheniscus demersus terminates superiorly by becoming coincident with the 

 cerebellar prominence. In Spheniscus minor, on the other hand, the temporal crest 

 resembles that of Spheniscus demersus in reaching the vertex of the cranium, but agrees 

 with Eudyptes inasmuch as it becomes coalescent superiorly with the cerebral and not 

 with the cerebellar portion of the skull. 



In respect of the temporal crest, Aptenodytes and Pygosceles closely resemble one 

 another. In both these genera the crest is less prominent than in either Spheniscus or 

 Eudyptes, and in l^oth the groove in front of it can scarcely be said to exist. In Ijotli 

 the crest resembles that of Eudyptes rather than of Spheniscus, inasmuch as it coalesces 

 above with the cerebral, and not with the cerebellar prominence, and in both it falls short 

 of the vertex and does not extend higher than the level of the base of the post-orbital 

 process. 



The supra-orbital grooves for the reception of the nasal glands are strongly j^ronounced 

 in every species of Penguin. In Eudyptes they are broader posteriorly than in other 

 genera, by reason of the presence of a broad, supra-orbital ledge of bone which, 

 projecting outwards from the external margin of the frontal bone posteriorly, con- 

 tributes to the formation of the groove in question. This ledge in Eudy2)tes extends 

 forwards nearly to the lachrymal bone, whereas in Spheniscus demersus and Spheniscus 



