Vol. XII. 

 1913 



] Shufkldt, Osfenlogy of Cereopsis novo'-hollandict'. 2IQ 



logically, they differ but little throughout the Anseres in so far 

 as I have examined them {Chen, Bninta, &c.) 



For a bird of its size, the sclerotal plates of the sclerotal circlet 

 or ring, in either eye, are both small and lew in number in Cereopsis. 

 With the form usually observed for them, they number, in either 

 eye, from 12 to 15, and are jiarticulaiiy narrow between their 

 inner and outer peripheries, in that part of the ring which is 

 situated anteriorly, the eyeball being lodged in the orbit as in life. 

 Without making a very minute study of them, the sclerotals of 

 the eyes of other Geese do not seem to be in any way markedly 

 different from those of Cereopsis ; they each have the usual 

 quadrilateral form, with the angles slightly rounded off. The 

 posterior ones approach the square in outHne, and the anterior 

 ones the parallelogram. 



The mandible in Cereopsis novcu-hollandicB is quite different, in 

 some respects, from that bone as we find it in Anser, Chen, or 

 Branta. It is likewise very unlike the lower jaw of such a species 

 as Tachyeres cinereus among the fuliguline Ducks, though we 

 begin to see its characters faintly reproduced in the mandible of 

 Chloephaga hyhrida, and very decidedly so in the mandible of 

 Chloephaga poliocephala. As a matter of fact, apart from the 

 question of size (the bone being one-third larger in Cereopsis), 

 the bones in these two Geese possess identically the same 

 characters. 



Viewed from above, the mandible is seen to have a somewhat 

 broad U-shaped outline, and is comparatively much shorter, 

 everything else being equal, than the mandible in other kinds of 

 Geese. For example, in Chen hyperboreus it is seen to be of the 

 long, somewhat narrow V-shaped pattern, with the dentary 

 portion very thick, its upper border longitudinally concave, and 

 correspondingly convex below. In either of these Geese the 

 symphysis is of fair depth, being convex inferiorly and concave 

 superiorly, and marked with the usual groups of nutrient foramina. 

 On the upper side these always appear to be confined mostly to 

 a double row, just within the anterior symphysial margin. 



The dentary portion of the mandible in Cereopsis is low, not 

 very thick from side to side, and externally lacks the deep and 

 curved groove found on the mandible in this locality in Chen, 

 Anser, Branta, and other Geese. We only find in this place in 

 Cereopsis, about half-way between the symphysis and ramus, an 

 elongate nutrient foramen, or the opening may be for a nerve exit. 

 (This is well seen in fig. i, Plate XXVIII.) 



The ramal portion of the mandible in Cereopsis is not much 

 loftier than the dentary part, while it is notably thin from side to 

 side. In Chen and Anser this ramal part is conspicuously high, 

 with a sharp, straight, superior border, the latter being rounded 

 below, and continuous with the inferior rounded dentary border 

 and that of the angular process which projects posteriorly. About 

 the middle of the ramal side, externally, and above the mid- 

 longitudinal line, opposite the point where the high part of the 



