124 MR. W. K. PARKER ON THE STRUCTURE 



Owl at once, and departing from JPodargus ; Steatornis also agrees with. Caprimulgus in 

 having the proximal part of the large flat antorbital (ecto-ethmoid) ossified. I mention 

 these things here to distinguish this type from the next to be described ; a full account 

 of it must be reserved for another time and place. 



On the Structure of the Face in the Giant Goatsucker (Podargns). 



Having been led up to Podargns by a series of marginal and of central Cuculine forms, 

 I am anxious in this paper to give the most intensely modified form of face that has as 

 yet come under my notice. A face and skull are present here which, like that of the 

 equally specialized skull of the Crocodile, give us a prolepsis of that of the Mammal, 

 with its hard palate, the last degree of desmognathism having been attained. 



This apparently ancient type, perhaps an early tertiary or even secondary waif, is also, 

 like the Oil-bird, an isomorph of the Owl, but not to the same degree. The huge upper 

 face, mimetic of the succulent leaf of an Aloe or a Mesembryanthemum, is mainly com- 

 posed of the premaxillaries and maxillaries (Plate XXIII. fig. 6). The figures already 

 given of the small and somewhat Passerine Pern-Owl (Plate XXI. figs. 8-11 and 

 Plate XXII. fig. 1) will help the student to understand the development of this thick, 

 arched, scooped, and although apparently solid, yet in reality spongy face. Prom the 

 terminal hook of the neb to the frontal region above, and to the truncated palatines below, 

 there is no trace of a suture. To make the division below the fore face on the one hand, 

 and the hind face and skull on the other, more complete, the jugal process of the maxil- 

 lary is absorbed, and the jugo-quadrato-jugal bar articulates with the maxillary inside 

 its dentary angle. Here, then, the only movement possible is at the cranio-facial 

 hinge ; for the pterygoids overlap and are tightly strapped to the palatines. The great 

 main hinge is behind, namely, that of the quadrate upon the auditory wall (fig. 7, q). 

 The motion here is almost as limited as in the claw-hinge of a Lobster. 



A rudiment of the basipterygoid is seen as a ridge, somewhat pointed in its middle, 

 which runs from the optic foramen below, and is soon indistinct. Between these ridges 

 the basifacial bar is subcarinate, and then flattens out, running into short bony wings, 

 which are the proximal parts of the ecto-ethmoids ; these are squarish flat cartilages 

 (Plate XXIII. fig. 7, pp). The septum nasi (fig. 7) is fiat, bony, and notched behind, 

 below the groove for the nasal nerve ; the hinge between the septum and the meso- 

 ethmoid (fig. 7, pe) is perfect. The fore part of the median ethmoid is slightly keeled 

 between the antorbitals ; its line is forwards and upwards equally. The alse nasi and 

 all the turbinals are unossified, and are extremely small and feeble ; for the descending 

 crus of each nasal, and the face-plate of the maxillaries, straighten the nasal cavities into 

 two widish tubes. The posterior trabecular splint, the parasphenoid, does not project in 

 front, and is very short ; the great anterior splints (premaxillaries) have few rivals in 

 relative size. With the nasal labyrinth so aborted the vomerine bones were likely to be 

 feeble. A flat band of fibrous tissue runs from a very soft bar of bone in front (v) to the 

 ethmo-palatine hooks behind (fig. 9, epa). Below, in front, we see this spongy wedge ; 

 it is higher at its smooth lower face than the great maxillo-palatine plate (mxp) to which 

 it is ankylosed. Above, in the end of the membranous vomerine band, there is a small 



