OF GALLINACEOUS BIRDS AND TINAMOUS. 157 



In the "Tetraoninae ' the antorbitals, however, are multiplied, and ossify. In Tetrao 

 cupido there are three, and in T. urogallus four cartilaginous pieces behind the middle 

 turbinal, instead of a continuous pars plana, as in the Mammals and Ostriches ; these 

 antorbitals are ossified. The middle ethmoid becomes very thick in Tetrao urogallus. 

 The orbito-sphenoidal region is but little indebted to the true orbital alse in Gallinae ; 

 and these alse are ossified continuously from the presphenoid, which is sometimes com- 

 posed of two pieces, as in Pavo. The orbital plates of the frontal wall-in the membra- 

 nous skull at this part, and supply the deficiencies of the true orbito-sphenoids. 

 Tetrao urogallus has small free orbito-sphenoids when examined during the first 

 summer. In neither the Fowl nor the Grouse is there any very definite outgrowth of 

 the ali-sphenoid answering to the " external pterygoid plate." In both these groups 

 the lachrymal has a strong superorbital plate ; but the descending process is very feeble 

 and styloid, most so in Lagopus and Tetrao. The nasals in both type and subtype are 

 lath-like, broad, ascend only a moderate way up the frontal region, and have rather 

 short anterior processes ; the outline between these processes, an upper and a lower, 

 is gently concave, more so than in the " Anatinse." The premaxillary is strong and 

 arched, and descending ; the dentary margin very sharp, and the palatine process a 

 mere splint. There is no maxillary ; and the prevomerine bones are very small in the 

 type, still smaller in the subtype. They are composed each of a flat scale-like body, 

 a slight ascending process (the rudiment of the shell-like outer portion of the bone in 

 the Ophidian and Lacertian), an inner process (feeble and flat in the Fowl, still feebler 

 in the Grouse), and a posterior or zygomatic process. 



This latter process is vicarious of the zygomatic process of the lost maxillary (which 

 exists as a mere rudiment in a few birds, as the Emeu, Night-Heron, Egret, and Swift') ; 

 and it overlaps the feeble malar style, which in its turn overlaps the equally feeble 

 quadrato-jugal. The vomer is in both groups a feeble style, bifurcate at the posterior 

 end ; it is double in Numida meleagris, one of the types, and broad in the subtypical 

 Tetrao urogallus. The feeble palatines are just a step above those of the " Stru- 

 thionidae ; " they have the long anterior, very ornithic splint. The pterygoids are 

 thick, and in both kinds articulate by a double head with the os quadratum. In a 

 chick nearly a week old I have found a small distinct " meso-pterygoid " between the 

 head of the pterygoid and the rostrum of the basi-sphenoid. The mandible in both 

 kinds is very strong : in the type the membranous space becomes filled up ; it is very 

 large and oval in the " Tetraonidse." The external and internal angular processes (the 

 latter the homologue of the Mammalian manuhrium mallei) are long in the type, the 

 internal being strong, the external sickle-shaped and flat. These parts have a similar 



' There is a rudiment also of this bone iu the small Egyptian Glede (Elanus melanopiertis) ; and in the Great 

 Penguin {Aptenodytes antaretica) (Osteol. Catal. Mus. Coll. Surg. vol. i. p. 216, no. 1118) there is a splint- 

 like, delicate maxillary, 3 inches m length. 



