126 MR. W. K. PARKER ON THE STRUCTURE 



The face of Steatomis is much like that of the Eared Owl (Asio otus), but the alee nasi are 

 much more ossified ; they are quite soft in the other two, and only the fore edge is left 

 cartilaginous ; its septum nasi is also bony. 



This agreement and disagreement, alternately, of these three Goatsuckers suggests the 

 probability that they each represent what were once large "subfamilies;" but their 

 characters, by their intense inosculation, show that they belong to one highly natural 

 group. 



The stapes of Bodargus presents a very curious and instructive example of this hyootic 

 structure. The otic portion, or basal plug (figs. 10 & 11, st), and the medio-stapedial bar 

 (mst) are quite normal. The " suprastapedial " (sst) is large and unossified, and so 

 also is the infrastapedial {ifst), which ends below, continuously, in a spatulate recurved 

 stylo-hyal. The thing, however, to be noticed is the huge roughly spoon-shaped extra- 

 stapedial (est), all bony, convex outside, concavo-carinate within, and pneumatic; the 

 upper margin is evenly sinuous, the lower and the end sublobate ; there is a fenestra 

 between it and the falcate suprastapedial (fig. 11). A ligament is seen growing from 

 the top of the extrastapedial spoon; and another larger ligament ties the supra- 

 stapedial to the prootic wall. The cartilage of the supra- and infrastapedial is con- 

 tinuous ; the line of the original arch or bar is from the mediostapedial to the infra- 

 stapedial, whilst the suprastapedial becomes a second head; the extrastapedial is a 

 conjagational outgrowth. The bifurcation of the rod above produces processes which 

 are the isomorphs of the capitular and tubercular processes of a true rib ; the supra- 

 stapedial resembles a tuberculum, and the mediostapedial a capitulum ; the shaft, as we 

 saw in the Martin, chondrifies in patches, the backwardly bent stylo-hyal reuniting 

 with the upper piece by a later chondrification of the infrastapedial tract. 



On the Structure of the Face in some other " Coccygomorphse." 

 In the Hornbills, the secondary growths of the trabecular and palatine arches, more 

 especially the former,. acquire the uttermost degree of prognathic development consistent 

 with the mechanism of a bird's skeleton as such. The result, taking in the correlated 

 modifications throughout the rest of the skeleton of these birds, is a form which makes the 

 conception of the living Bterodactyle an easy effort of the fancy. Pneumatic overgrowths, 

 of such a size as we see in the larger species, intensify the grotesqueness of the creature ; 

 for the aneurismal bursting of the bony walls by the imprisoned breath has resulted in 

 their huge air-chambers, walled in merely by the horny epiderm and its filmy quick. 

 For a figure of the palate of Buceros bicomis the reader is referred to Professor Huxley's 

 paper (op. cit. p. 446, fig. 28). Here the bony bar between the apertures marked a is the 

 foot of the Chelonian vomer, separated from its posterior portion by a membranous 

 space, and ankylosed to its surroundings, namely, the maxillo-palatines and the coalesced 

 interpalatines, behind ; for these larger species have a palatinal hard palate. The styloid 

 posterior part is ankylosed with the palatines at their upper or true commissure. I see a 

 similar structure in B. ruficollis, Temm. ; but the interpalatines are imperfect, and the 

 form of the vomerine foot is not so easily traceable. In this species the notch which 

 forms the cranio-facial hinge is reconverted into a fenestra by a tuberous growth of bone, 



