26 ALUS. [Vol. XVIII. 



from which it arises, its lateral edges being extended to form 

 small processes which project laterally, downward and forward. 

 They are rounded on their superior surfaces, but flat on their 

 inferior, postero-ventral surfaces, where they rest, on each side, 

 upon the dorsal edge and dorsal surface of the anterior portion of 

 the vomer. The median part of the beak is compressed laterally, 

 and has a rounded, median, anterior edge. Its ventral end lies 

 between the dorsal ends of the lateral articular processes of the 

 vomer, fitting into a deep median indentation in the anterior edge 

 of that bone. The postero-dorsal edge of the beak abuts against 

 the antero-ventral edge of the ethmoid, the anterior end of the lat- 

 ter bone being slightly differentiated as an antero-median process. 

 The superior surfaces, both of the beak and of its lateral proc- 

 esses, are seen in dorsal views of the skull. In ventral views the 

 anterior end of the beak alone is seen, the lateral processes, and 

 often the beak also, being hidden from view by the enlarged an- 

 terior end of the vomer. The beak gives articulation to the in- 

 ternal surface of the rostrale. The lateral processes do not give 

 direct articulation to any bony or cartilaginous structures. Slightly 

 posterior to them there is, on each side, a lateral process of the 

 basis cranii which caps the ventral surface of a ventro-lateral 

 process of the ethmoid, and gives articulation to the palatine. 



In certain of the Characinidse, Sagemehl's figures seem to indi- 

 cate that the beak of Scomber, or that structure and its lateral 

 processes also, are ossified as parts of a greatly developed ethmoid. 

 The articulations in the Characinidse are, however, not exactly 

 similar to those in Scomber, and the ethmoid of the former fishes 

 is said by Sagemehl to be, in part, a dermal bone. The lateral 

 processes, in particular, are greatly developed in certain Cliar- 

 acinidae, and they may represent the lateral processes of the beak 

 of Scomber fused with the ventro-lateral processes of the ethmoid. 



At the dorso-posterior and ventro-posterior edges of the antor- 

 bital cartilage of Scomber there are short, median, cartilaginous 

 processes projecting backward. The ventral surface of the dorsal 

 process and the dorsal surface of the ventral one are both raised 

 in slight, median ridges. These ridges are usually connected, 

 along the median line of the posterior surface of the antorbital 

 cartilage, by a similar, more or less pronounced ridge in the cartil- 



