212 Shufeldt, Osteology of Cereopsis novce-hollandia; . Tist^A^rii 



entirely completed in bone ; but where it is large, this antero- 

 palatal portion oi the cranium is correspondingly lacking in 

 osseous com})letion, and so more or less weak in structure. 



Cereopsis possesses only a partial nasal septum performed in bone, 

 and this, in the adult, is confined to the posterior rhinal space, 

 between the nasals, and somewhat anterior to them. 



As will be noted from an examination of fig. 23, PI. XXXII., the 

 facial part of the cranium in Tachyeres cinereus has an aspect more 

 after the order of what we see in the skull of an average Goose 

 than has the corresponding cranial region in Cereopsis, for in 

 Tachyeres the line of the culmen — from the concave fronto-cranial 

 area, situated mesially between the long, forward-projecting 

 portions of the lacrymals to the anterior extremity of the superior 

 mandible — is very gently concaved, as it is in most species of 

 Anser and Brania. Tachyeres, too, has large, elliptical external 

 narial openings, with a complete absence of any osseous nasal 

 septum. The osseous tomia are thin and very sharp-edged, 

 while the sides of the mandibular walls are deep in this species, 

 and the distance between them considerable, thus rendering the 

 concavity formed by the bones of this upper mandible on its 

 lower side unusually spacious. 



Chen hyperhorcus has an osseous superior mandil^le very 

 different from this, and even more so as compared with that part 

 of the cranium in Cereopsis. Chen has this part of its skull — 

 which is in keeping with all the rest of it — thick and strong. 

 From its basal portion to its apex it tapers considerably to the 

 rounded extremity, and the line of the blunt edge of either osseous 

 tomium is convex upwards for its entire length. The osseous 

 nasal septum is imperfect in this Goose, and what there is of it 

 is situated posteriorly above the maxillo-palatine mass. Either 

 external narial aperture is large and subelliptical, and the distance 

 between them, superiorly, narrow at its middle part. The con- 

 cavity on the under side of the superior mandible is shallow, and 

 the surface roughened. The mesial foramen occurring there in 

 so many of the Anser es is usually very small in this genus. 

 Between the apex and the ending of the maxillo-palatine mass 

 posteriorly, in the mid-longitudinal line, there is a long, deep 

 furrow ; while on either side of this, between it and the tomial 

 border, there is a chain of roughened tubercles. Each commences 

 where the palatine of the same side is inserted, and terminates at 

 a point about half-way to the apex, being largest posteriorly, and 

 becoming gradually smaller to their anterior disappearance. No 

 other Goose known to me possesses these, and there is not 

 the slightest evidence of their presence either in Anser or 

 Br ant a. 



On cither side the infero-posterior process of the premaxillary- — 

 by some called the nasal process of that bone — is produced back- 

 ward in the skulls of many species of Geese, but not in all. It is 

 conspicuously so in Tachyeres, Anser, Branta, Chen, Hynieno- 

 lamiis, and Chloephaga poliocephala, but much less so in Chloephaga 



