STUDIES or THE MACEOCHIEES. 



319 



of these two species is of so slight a nature that we cannot 

 readily distinguish them ; for if a series of each were mixed up 

 before me, there would be no difficulty wbatever in rapidly 

 selecting the skeletons which belong to either of these two 

 species. As I proceed with my detailed descriptions, I will 

 point out the more marked of these differences, while my obser- 

 vations must be considered as applying directly to the skeleton 

 of T. meocicanus, unless otherwise specified. 



Of the Skull (PI. XVIII. fig. 8, and PI. XIX.).— Viewing this 

 part of the skeleton from above, we find that a strong transverse 

 line separates the superior osseous mandible from the fronto- 

 lacrymal region, which latter arches upwards and backwards from 

 it. This superior mandibular portion of the bony beak is rather 

 low from above downwards, broad at the base, tapering rapidly 

 to the tip, while its osseous tomia are sharp, and the culmen is a 

 graceful, rounded, and unbroken arch from the frontal region to 

 the tip of the beak. The narial apertures at its sides face 

 upwards and outwards ; they are large, of an elliptical outline, 

 and with smooth, rounded edges. 



Each lacrymal bone is a somewhat slender, peculiarly-shaped 

 element of an /-like form, which freely articulates by its supero- 

 mesial surface or moiety with a vertical facet offered by tlie cor- 

 responding frontal. Its upper end rises above the surrounding 

 surface of the skull, while its lower extremity fails to reach the 

 quadrat o-jugal bar below. 



The region between the orbital peripheries on the superior 

 aspect of this skull is very narrow, and presents a shallow longi- 

 tudinal furrow. Posterior to this part the parietal region is 

 characterized by two laterally placed roundly convexed eminences, 

 with a rather better marked median longitudinal track between 

 them, being the continuation of the furrow jus>t alluded to in the 

 interorbital region. 



Viewing the skull of this Trogon upon its lateral aspect, this 

 marked rounding of the parietal region lends to it rather an 

 unusual configuration for the cranium among birds. 



Upon this view, too, we must note the rudimentary condition 

 of the sphenotic process, while the squamosal apophysis below it is 

 large and conspicuous. The interorbital septum, ^e;* s^, is entire 

 though very thin, wdiile, on the other hand, the foramina at the 

 posterior aspect of the orbital cavity are far larger than is required 

 for the nerves to which they severally give passage ; especially 



