666 ALLIS. (Vou. XII. 
to the rest of the so-called palatine arch in the Cyprinidae 
(Sagemehl) ; that the coronoid cartilage is sometimes found as 
a separate piece, as in Lepidosteus (No. 129, p. 268); and that 
the palatine and pterygoid elements may (No. 118, p. I1), or 
generally do (No. 97, p. 403), fuse late. Hubrecht’s figures 
(No. 59, Figs. 1 and 2, Pl. XVII) showing the arrangement 
of the labial cartilages in Chimaera and Callorhynchus also 
strikingly suggest the probability of parts of two arches being 
connected with the mandible. 
Further evidence in support of this is found in the develop- 
ment of the arches in Salmo, Pristiurus, and Raja, as given 
by Parker. In Salmo (No. 84, Fig. 1, Pl. III) the hyomandib- 
ular is shown as the proximal element of the hyoid arch, the 
metapterygoid as the proximal or the two proximal elements of 
the mandibular arch, and the palato-pterygoid as an entirely 
separate piece lying in front of the upper end of the mandibular 
arch. In Pristiurus and Raja (No. 85, pp. 214, 216, and 219) 
the spiracular cartilage, or metapterygoid, and the hyomandibu- 
lar arise as separate pieces at the distal ends of the mandibular 
and hyoid arches respectively. The spiracle lies between 
the two elements. In Raja it is an anterior process of the 
upper end of the hyoid arch that becomes the hyomandibu- 
lar, while a posterior process in the mandibular arch becomes 
the metapterygoid. This seems to indicate that the hyoman- 
dibular may be in Raja an infrapharyngeal instead of a supra- 
pharyngeal element. It may possibly be such in Amia, also, 
or it may be in one line of descent one of these elements, in 
another the other, and in still another the two combined, thus 
accounting for its varying and puzzling relations to the facial 
nerve. That either one or the other of the two pharyngeal 
elements may acquire an articulation with the skull is seen in 
the branchial arches. 
Pollard’s assertion (No. 98, p. 24) that “the supposed hyo- 
mandibular of Elasmobranchs does not correspond to the 
hyomandibular of Teleostei and sturgeons,” is based in part on 
certain errors, for the levator maxillae superioris muscle of elas- 
mobranchs is not, if I am right, the homologue of the levator 
arcus palatini of teleosts, and there is some question as to its 
