SKULL OF THE ^GITHOGNATHOUS BIRDS. 267 



able character, the possession of distinct palatine plates in the maxillary region, in 

 addition to the maxillo-palatine processes, is most important; for these bones, in a 

 descending survey, are not found until we reach the Batrachians and Ganoid fishes. I 

 am speaking of forms still existent ; they may turn up in fossil Eeptilia. 



Then we have just seen that in Central and South America certain tenuirostral and 

 the feebler of the conirostral types have these bones (Mniotiltidse and their allies on 

 the one hand, and Tanagridse on the other). However near or far off these types may 

 lie in their relation to each other, the existence of any one marked character in 

 the species of families belonging to a continuous geographical territory indicates a 

 common root or cause. In an unnamed species of Icterus I find such a similarity of 

 the whole skull and face to that of a Starling, on one hand, and of the Cardinal and the 

 Buntings on the other, that I am at a loss to characterize it otherwise than by saying 

 that it is an intermediate type. Yet on the whole, with a narrower face and a broader 

 and a more capacious cranium, it has altogether a stronger structure than that of any 

 of these birds. 



The straight pterygoids are quite normal both in possessing a moderate epipterygoid 

 hook and in giving off a mesopterygoid segment. The transpalatine is spongy and 

 angular, and the whole of that region is steep. Stout to the fore end, the palatines lose 

 themselves in the solid, decurved, high-backed rostrum (Plate XLIX. figs 1 & ^,j)r.pa). 

 The interpalatine spurs {i.])a) are not large, nor are the ethmo-palatine coils much 

 extended [e.pa). The palato-maxillaries (p.mx) are somewhat ankylosed to the prae- 

 palatal bars ; but their middle is opposite the dentary angle of the prsemaxillaries, so 

 that they are thus excluded from that category, and seem to belong to the outworks of 

 the palatine arch. 



The vomer (v) is broad in front, and has very converging crura, which are 

 ankylosed to the ethmo-palatines. Between each shoulder and the pedicle of 

 the maxillo-palatine there is a solid subcentral septo-maxillary (s.wi.i) ; and also on 

 the inturned part of the nasal floor (n. f) there are two more ossicles on each side, 

 besides lesser bones. The septum nasi (s. n), which is alate, is ossified considerably ; it 

 is strongly ribbed. The alinasal and inferior turbinals are soft ; the former are not seen 

 from below, on account of the great development of the nasal floor. The delicately 

 pedunculate maxillo-palatines end in a large, flat, cultrate blade, with sharply produced 

 points, giving it a falcate character; the inner edge of this scythe is serrate. The 

 lacrymal, like that of Sturnella (fig. 4, I), is long and pupiform, and has the form and 

 position seen in Fipm, Phjtotoma, Tanagra, and the larger Crows. At its base 

 it has a large, distinct, ovoidal os uncinatum(o. u). The general ecto-ethmoidal mass 

 projects outwards less than in the Passerine types generally. The alinasal region 

 is soft. 



VOL. X. — PART VI. No. o.-^June 1st, 1878. 



