THE SKULL IN THE WOODPECKERS AND WRYNECKS. 17 



The jugals (/) are slender, save at the quadrate end, where they are very solid and 

 inhooked. 



Altogether this small far-western type is extremely instructive, and helps to lead the 

 imagination down to extinct types in which the characters of the Hemipod, the Low 

 Passerine, and the "Woodpecker were existent in one generalized form — a form and a type 

 only a step or two above the raft-breasted Ostrich tribe. 



On the Development of the Face in the Subfamily Yungidse : example 

 Yunx torquilla. 



We now come to the feeblest members of the " Celeomorphse;" yet the Wrynecks 

 are stout little birds, with the same restless energetic character as the larger types. 



The possession of several nestlings of this form, the gift of Mr. Dines, has enabled me 

 to work at a still earlier condition than that of the youngest specimen of Gecinus 

 viridis. 



The palate (Plate IV. fig. 3) shows that these birds are true Woodpeckers, and have 

 no special affinity to the Crow and its allies. 



Here we have the same form of occipital condyle (o. c), the same massive broad " basi- 

 temporal " plate (b.t), the rudimentary " basipterygoids" (b.pg), and, what is very instruc- 

 tive, an explanation of the very remarkable cowrie-shaped tympanum seen in those types. 



The " basitemporal " forms a large retral hook where it joins the " exoccipital " (e.o), 

 and is then roundly scooped at its edge. Here the lobular growths of the adult are seen 

 to be due to the presence of a " tympanic chain ; " three of these bones are now to be 

 counted on each side (Plate II. fig. 1, as compared with Plate IV. fig. 3, ty). 



In Yunx the " parasphenoidal rostrum " (pa.s) is much longer than in JPicus, and the 

 face much shorter, especially the prasmaxillary (px). This is most remarkable when 

 compared with Gecinus and Semilophus : something is due, however, to age ; for these 

 specimens are very young. 



The solid part of the prsemaxillary is very short indeed; but the three main bars 

 are long and extremely slender (d.px, p.px) ; they have the same relations as in JPicus. 

 The nasal septum, with its thick trabecular base, is still unossified, and indeed scarcely 

 hardens at all in this type, nor do the turbinals. Here the prsenasal cartilage (fig. 3,p.n) 

 is still large. 



There are no septo-maxillaries at this stage ; nor am I aware of their existence in the 

 adult*. The " vomers," however, are very noticeable. At first I expected to find them 

 partly preformed in hyaline cartilage, as in the " Coracomorphse," especially as Semi- 

 lophus retains in its adult state its large or pr&vomerine labial plate. It is not so ; they 

 arise, as in Gecinus viridis, in a band of soft connective web on each side of a remarkable 

 recess in the mucous membrane of the nose, the azygous counterpart of those paired 

 recesses called in Man the " sphenoidal sinuses " (Plate IV. fig. 11, v, m.sph). 



Below the vomers is the palatal mucous membrane (Plate IV. figs. 10, 11, v). Seen 

 from below (fig. 4, v) they are remarkably like those of a young Passerine, being pointed 



* The adult skull may be seen in the macerated condition in the College of Surgeons ; it was prepared by me with 

 the other bones, and drawn thirty-two years ago. 



SECOND SERIES. — ZOOLOGY, VOL. I. D 



