176 EDWARD PHELPS ALLIS, JR. 
says that this raphe is sometimes transverse to the line of the 
apertures. The aboral, or posterior nasal aperture of the adult 
Teleostei thus corresponds to the aboral, or antero-lateral aper- 
ture of the adult Plagiostomi, and the current of water through 
the apertures of the former fishes is the reverse of that in the 
latter. The nasal pit is said by Burne to be completely bridged 
in nearly all, but not all, of the Teleostei, and this bridge is 
currently considered to be the homologue of the two half bridges 
of the Plagiostomi fused with each other above the nasal groove. 
No alar cartilage is however ever found, so far as I know, related 
to this bridge in these fishes. Burne describes mucous folds 
which project inward from the internal surface of the nasal 
bridge and that would seem to correspond to the nasal valves of 
the Plagiostomi. 
In the Holostei and Crossopterygii the nasal apertures and 
nasal bridge are apparently strictly similar to those in the 
Teleostei. 
Labial and supramandibular folds and furrows are well de- 
veloped in many if not in all of the Teleostei, Holostei and 
Crossopterygu, and I have, in an earlier work (Allis, ’00), 
described them in certain of these fishes. The secondary upper 
lip is represented, in all of these fishes, in the ventral edge ofthe 
labial fold, and it is always continuous in the median line with 
its fellow of the opposite side. It passes between the nasal 
apertures and the upper edge of the primary cavity of the mouth, 
and the space included between it and the primary lip forms a 
secondary addition to the buccal cavity. The maxillary and 
premaxillary bones lie in this secondary upper lip, as do the 
labial cartilages of the Selachii in the secondary upper lips of 
those fishes, and, where teeth are developed in relation to these 
bones, they form a dental arcade which lies external to and 
concentric with the primary, palatoquadrate arcade. 
A supramaxillary fold is found, more or less developed in 
many of these same fishes, the related furrow there extending 
upward internal to the lacrimal bone, or to it and the anterior 
suborbital bone. This furrow I have already described in 
Scomber (Allis, 703, p. 64) as an important fold which “extends 
