AND DEVELOPMENT OF THE BIRD'S SKULL. 113 



the Goatsuckers least : the Goatsucker, agreeing in very important characters with 

 JPodargus and Steatornis on the one hand, and with the Trogons on the other, lies alto- 

 gether on a lower and more embryonic level than the " Coracomorphse," especially those 

 to which the Swifts are allied. These other " Families " may take their place for the 

 present with the other equally discordant " Coccygomorphse," and the term "Cypse- 

 lomorphae " be allowed to drop. The Swift, so far as its cranio-facial morphology is 

 concerned, is an " jEgithognath," and I have treated of it in a paper which has been 

 read at the Zoological Society. The Goatsucker and Humming-bird come under the 

 plan of the present memoir. 



On the Structure of the Face in Caprimulgus europseus. 



The moth-shaped mouth of the Eern-Owl is roofed in in a manner peculiar to itself ; 

 but its gaping face is developed by a process in nowise different from that which operates 

 in its nearer or more distant relations. 



In the basal figure (Plate XXI. fig. 8) the trabecular structures are largely hidden 

 by the palatines ; and to understand this most frog-Like of all the skulls of the " Carinatse," 

 the student must examine the actual object. 



Bony matter is here spun to its uttermost degree of fineness, and the resulting sub- 

 stance is something more like feather than bone. The whole shape is flattened and 

 outspread, and, as in the Batrachia, the originally flat broad trabeculse have retained 

 much of their primary form. In front, however (Plate XXI. fig. 8, and Plate XXII. 

 fig. 1, sn), they are narrowed, and quite absorbed anteriorly, as in all other birds ; at 

 least, the azygous prenasal outgrowth is early absorbed. Behind, the bony trumpets 

 that "grow from the ossifying apices of the trabeculse spread far apart, forming the 

 " anterior tympanic recesses " (atr), and enclosing the V-shaped double Eustachian 

 tube (eu). 



The trabeculse, as they surround and converge in front of the pituitary body, are con- 

 verted into a broad and winged mass of bone by the parasphenoid (pas), and at each 

 side of the common Eustachian opening there are two " conjugational processes " 

 (fig. 8, bpg). The lower of these is the " basipterygoid " proper, and it carries the free 

 cartilaginous plate for pterygoidean hingement ; this flat broad process looks forward. 

 Above this is a retral hook, which merely holds a ligament. 



As in the Erog, the trabecular and parasphenoidal structures project but little below 

 the lateral ethmoids (Plate XXI. fig. 8, pp), so that each pars plana seems to grow out 

 from the median, beam-like, large-winged outgrowths : they have carried the " palatine 

 conjugational process " (ou) with them. This does not ossify into an " os uncinatum," as 

 is common in the " Cuculinee," but remains persistently soft as hyaline cartilage. 



In front, between these ecto-ethmoidal wings, the broad parasphenoid and the trabecular 

 base of the meso-ethmoid each separately taper to a point ; and here the first facial arch 

 has part of its long commissure absorbed to form the cranio-facial hinge. 



In the pin-feathered nestling the trabecular base of the septum nasi (Plate XXII. 

 fig. 1, sn) is rather solid, but the azygous rostrum has been already absorbed. In the 

 adult (Plate XXI. fig. 8, sn) the " posterior septal bone " is rather solid than spongy, and 



