THE SKULL OF CHOLERA. 



127 



surface, and this eminence rests upon the little eminence on the 

 dorsal surface of the ala nasalis (cartilage kn) that is described 

 in my earlier work (Allis, 1917 b), the two cartilages there being 

 strongly but flexibly attached to each other by connective or 

 ligamentous tissues. The pedicel of the cartilage turns sharply 

 mesially, in a rounded angle, and passing through a notch in 

 the postero- ventrolateral edge of the nasal capsule runs along 

 the posterolateral edge of the posterolateral nasal aperture and 

 reaches a small perforation of the chondrocranium that lies 

 immediately ventral to the ventro- posterior edge of the fenestra 

 nasalis. This perforation of the chondrocranium is filled with 

 ligamentous tissues, and to these tissues the foot of the pedicel 

 is strongly but flexibly attached, the position of this pedicel 

 strongly resembling that of the anterior upper labial in Hetero- 

 dontus (Allis, 19176). 



On the ventral edge of the cartilage fg, at about the posterior 

 third of the length of its plate-like portion, there is a slender 

 curved process which projects ventrally into a ridge on the 

 internal surface of the nasal portion of the naso-labial fold, 

 this ridge quite certainly representing the tissues that enclose 

 the process [3 of the ala nasalis of the Plagiostomi (Allis, 1917 b). 

 Because of its position, this process of the cartilage fg may be 

 called the nasal-fold process. It is thinner than the body of the 

 cartilage fg, is flexible, and in many instances seems to be a 

 primarily independent piece of cartilage that has secondarily 

 and not completely fused with the cartilage fg. In several 

 instances there was a foramen between the base of this process 

 and the body of the cartilage, this foramen giving passage to 

 a delicate nerve which was apparently a branch of the nervus 

 maxillaris trigemini. In other specimens this nerve passed 

 between the process and a crescentic cartilage described imme- 

 diately below. The cartilage I is attached to the inner surface 

 of the cartilage fg immediately beyond the base of this nasal-fold 

 process. 



In the hollow of the curve formed by the posterior edge of the 

 nasal-fold process of the cartilage fg and the ventro-posterior 

 portion of the body of that cartilage, lies the crescentic piece 

 of cartilage just above referred to. This cartilage is of the 

 same consistence as the nasal-fold process, and lies, as that 

 process does, in the ridge on the internal surface of the naso- 

 labial fold, and it is apparently the cartilage e of Hubrecht's 

 descriptions of Chlmcera monstrosa. Both it and the nasal-fold 

 process of the cartilage fg are shown in one of Luther's figures 

 of the latter fish (1909 6, p. 37), and K. Furbringer (1903)" also 

 refers to both of them, the two together being considered by 

 him to represent the cartilage e of Hubrecht's descriptions. In 

 Chimcera colliei the crescentic cartilage is connected with the 

 cartilage d, which I consider to be the posterior upper labial, 

 by a band of tough fibrous tissue which passes across the external 

 surface of the cartilage fg, a slip of the tissues being sent antero- 



