RHYNOHOPIN^, SKIMMERS. 713 



processes, and of the character of the dtpression for the nasal gland. The convex 

 borders of the fossa; do not nearly aiiproach each other on the median line, bnt are 

 widely separated. The fossie themselves are narrow and imperfect, not neaily contain- 

 ing the whole of the glands, which conseqnently project gi'catly over the cd^^e of the 

 orbit. The foss;e are continued each as a well-marked groove, nnder the anteorbital 

 processes, their ducts passing throiij;b a very large foramen on their way to the lining 

 membrane of the nose. The interortital septnm is complete. The olfactory nene 

 mns along iu a furrow so deep as to be almost a canal. From the corajileteuess ot the 

 septum, between the orbits, the foramina of exit of the nerves at the posterior part of 

 the orbits are more perfect and less closely approximated than in the other subfamilies. 

 The conjointed bases of the sphenoid and ethmoid, a\ hich form the inferior bordi'r of the 

 septum, and along which the palatal and vomerine bones slide, is much thicker and 

 stouter than ordinary, and does not extend nearly so far forward, nor has it an acute 

 apex nor deeply concave anterior edge. 



The forehead is exceedingly broad, and slopes down from the vertex at an tinusually 

 great angle of descent. In its centre it is slightly concave laterally, owing to the de- 

 velopment and prominence of the anteorbital processes. Anterior to these it is perfectly 

 plane, wide, with parallel, straight sides, dipping down deeply with a square truncated 

 base which forms, wijh the superior mandible, the very peculiar fronto-niazillary 

 suture. This " articulation " admits of a far greater degree of motion than exists in the 

 other subfamilies, and greatly exceeds that usually found among birds, excepting, of 

 course, the Psittaci. The connection between the bones of the cranium and superior 

 mandible is perfectly straight and transverse ; very wide (being the whole width of 

 the broad frontal bone), and at the same time exceedingly thin and elastic. On the 

 superior surface of the suture there is a deep groove between the bones, a little wider 

 at either extremity than in the middle, bnt the under surface is quite smooth. The 

 osseo-cartilaginous connective substance is pliable and elastic, so much so, that in an 

 old and dried preparation before me, the original mobility of the parts is in a great 

 measure retained. 



In the adult skull bt-fore me there are no discernible traces of any nasal bones, prop- 

 erly speaking ; but the suture is formed entirely by the apposed terminations of the 

 broad frontal, and equally broad mesial process of the intermaxillary. That portion 

 of bone usually known as the "maxillary" or descending process of the nasal, exists, 

 unusually developed, and in an unusual position. Below it is iirmly anchylosed and 

 completely consolidated with the mandibular ramus, just anterior to the maJar anchy- 

 losis. From this base it extends upward and backward as a long, very slender, com- 

 pressed bone, running parallel with, but not touching the sides of, the os frontis, to be 

 received by this thin, flat, laterally expanded termination into a slight depression in 

 the under and anterior edge of the ante-orbital process. As it participates in all the 

 movements of the upper jaw, its union with the ante-orbital processes is a movable 

 suture, of apparently the same general characters as the fronto-maxillary suture, of 

 which it is to be considered as really a part. 



The other elements which assist to produce the movements of the upper jaw,'are all 

 by their shape or position subservient to its increased mobility. The ossa pedicellata 

 are long and strong, and especially remarkable for the increased development of their 

 malar eminences, which carry the ends of the zygomata far outward and downward, 

 and thus are enabled, with an ordinary degree ot motion of the tympanic bones them- 

 selves, to impress upon the malar, and through them upon the superior maxillary bones, 

 an increased amount of motion. They also produce a somewhat peculiar shape of the 

 articulaticg surface for the inferior mandible. The orbital processes of the tympanic 

 hones are very short, small, and exceedingly acute. The pterygoid bones prctseut no 

 special peculiarities of shape, but, from the narrowness of the skull, are not so widely 

 divergent as in the other subfamilies. The palatal bones are remarkable for stout- 

 ness and width, and also for the solidity and extent of their anchylosis with the supe- 

 rior maxillaries. The outline of their posterior margins is very oblique, and they 

 terminate with qnite prominent processes for the pterygo-palatal articulation. Poste- 

 riorly their inferior surfaces have considerable lateral concavity from the elevation of 

 their borders ; more anteriorly they are plane and smooth, their surface being directly 

 continuous with the plane of the maxillaries. The vomer is shorter than usual, and 

 bifurcate to a less extent. The malar bones are perfectly straight ; their axes in a line 

 with the general inclination of the axes of the mandibular processes of tbe intermax- 

 illary ; but just at their union with the maxillary bones there is a considerable angle 

 formed, from the increased divergence of the latter at that point. They are throughout 

 laterally compressed, except just at their anterior extremities, where they become hor- 

 izontally depressed and flattened, to give them the necessary mobility of elasticity iu 

 au upward and downward direction. 



The intermaxillary bone is entirely peculiar iu shape and general characters. It 

 is remarkable for the preponderance in size of the mesial over the mandibular pro- 

 cesses, and for the unusual extent to which the latter are united with the former 



