DEVELOPMENT OF THE SKULL IN THE OSTRICH TKIBE. 177 



T. rohistus. The nasal processes of the intermaxillaries {px.) are entirely soldered 

 together in both kinds, but they are very pluvialine, as may be seen by comparing them 

 with those of the Lapwing ; they also agree, in the main, with those of the Apteryx, 

 save that the tips come close together and are very narrow, as in most of the " Pluvialinaj " 

 (Plate XV. fig. %,px.). The lateral grooves, the beautiful vascular punctse, the short 

 angular processes, and the large, long, flat palatine processes of the intermaxillaries 

 (Plate XV. fig. 3) are all strictly struthious, as may be seen by a comparison of the 

 numerous figures showing these parts. In T. variegatus the ascending process of the 

 prevomer is small, and the pedate proximal process is not marked out from the body 

 of the bone (Plate XV. fig. 2, p. v.) ; in T. rohustus, however, we come nearer the 

 " Gallinaceae " proper, the Megapods, the Sandgrouse, the Hemipods, and the innume- 

 rable Corvine, Sylviine, Fringilline, and other related groups in the differentiation of 

 this remarkable process, long supposed to be the inferior turbinal. In T. robustus, this 

 narrow, flat, curled, gradually widening process is turned somewhat backward ; and as 

 it passes also inwards comes down upon the anterior process of the palatine, and 

 coalesces with its upper and inner edge (Plate XV. figs. 6, 7, p.v.). The delicate angular 

 process of the intermaxillary is 1| line long in T. variegatus, and 6 lines long in 

 T. robustus, in which it is continued to the foot of the descending process of the nasal 

 (Plate XV. figs. 6, 7) ; feeble, indeed, and clubbed at its end. The very large " vomer '' 

 (Plate XV. fig. 2, v.), deeply cleft behind, and having two long forks in front, is struthious 

 enough ; in the Hemipods it is extremely short and broad ; in the Sandgrouse and 

 Pigeons seldom present at all ; in the " Phasianinae " and " Tetraoninse " it is very 

 feeble, and not much stronger in the Megapods ; in the Plovers and Hails it attains a 

 medium size ; but the Tinamous hold with the large Ostriches in this most important 

 and very reliable character. The nasals (n.) of the Tinamous come still nearer to those 

 of the Plovers than do those of the Apteryx ; but the posterior portion is so completely 

 amalgamated with the frontal, ethmoid, and lacrymal, that it cannot be told how much 

 nearer they came to the Plover's nasals. To all appearance there is but little difference ; 

 and so also as to the frontals (f.), especially if we compare the Tinamous skull with such 

 species as have but little of the frontal developed below and beyond the nasal gland. 

 So also the lacrymals (I.) ; these have lost their superorbital process, and like the Casso- 

 wary, have no antorbital fenestra. The narrowest part of the combined frontals is only 

 3 lines in T. robustus, scarcely more than 2 lines in T. variegatus ; the outer margin being 

 also bevelled deeply for the nasal gland, and that also almost to the postorbital region. 

 But in Vanellus, Charadrius, and others, the frontals run below and beyond the gland, and 

 are very wide ; I have already shown (Trans. Zool. Soc. vol. v.) how this is supplemented 

 in Tinamus robustus. In that bird the superorbital chain of bones is single, with one 

 intercalary bone on each side ; but T. variegatus has two rows (Plate XV. fig. 3, s.o.b.) 

 all along, about 14 or 15 on each side. I have already compared these to the super- 

 orbitals of the Skink-lizards, Blind-worms, and Trigonal Cayman, and have noticed their 

 presence in another bird, viz., the Trumpeter (Psophia crepitans), only in an enfeebled 



MDCCCLXVI. 2 c 



