40 MR. W. P. PYCRAPT ON THE [May 2, 



iii. The Skull of the Nestling. (PI. II. figs. 1 & 1 a.) 



It is a matter for regret that the British Museum Collection of 

 nestling skulls of Euryla3mida3 is limited to half -grown specimens 

 of Etirylcemus ochromelas , and these have suffered somewhat 

 severely as a consequence of having been preserved in formol. 



a. Cartilage-hones. 



The basioccipital cannot, in these skvills, be more than imper- 

 fectly traced, having become fused with the lateral occipitals. 



The exoccipital, or lateral occipital, is a large, more or less 

 linguifoi'm plate presenting a broad convex external border, the 

 infei'ior segment of which forms the tympanic cavity, while the 

 superior arc of the cm've is applied in part to the base of the 

 squamosal and in part to the parietal. It is bounded mesiad 

 by the supraoccipital and tlie occipital foramen, which excavate 

 a considerable moiety fi'om its internal boixler. Inasmuch as the 

 exoccipital comes into contact with the jDarietal, it resembles that 

 of the Cuculidte. 



The supraoccipital is short antero-posteriorly, and is not yet 

 ossified ; its superior margin being W-shaped and leaving a large 

 fontanelle between itself and the parietals. Laterad it has fused 

 with the lateral occipitals, leaving only a faint tell-tale notch to 

 indicate the junction. 



Thepro-,epi-, and opisthotic bones are now completely concealed 

 when the skull is viewed externally. 



The hasisjyJienoid is also concealed, being underfloored by the 

 basitempoial plate. 



The alisphenoid appears as an oblong plate, having its long- 

 axis horizontal. 



The orhito-sphenoid is still membranous, while the presphenoid 

 has fused with the basisphenoid. 



The mesethmoid has only just commenced to ossif}'-, and is 

 represented by a small linguiform plate supporting the yet carti- 

 laginous antorbital plate, and bounded in front by the cranio- 

 facial fissure. The interorbital septum foiined by the backward 

 extension of the plate is as yet only outlined in cai'tilage. 



The olfactory cavities occupy less than half of the so-called 

 anterior narial apertures as seen in the dried skull. The actual 

 anterior nares, in Uiorykamus ochromelas for example, are small 

 and round, and j^laced at the extreme anterior angle formed by the 

 divarication of the nasal and maxillary processes of the premaxilla. 

 The superioi' segment of this circle is formed by membiane, and 

 this extends backwards and inwards as a subtubular sheet to be 

 attached to the antorbital plate. Mesially this tube is shut in by 

 the nasal septum, and inferioily by membrane forming the roof 

 of the palate. Within the chambei' thus formed lies a long, 

 somewhat spatulate cartilaginous turbinal extending backwards, 

 by a short stalk, to the anteiior end of the vomer. The free end 



