98 
EDWARD PHELPS ALLIS. 
In Rai a clay at a (3?]. 6, figs. 1-3) tlie posterior (oral) edge 
of the nasal flap of either side occupies about two-fifths of the 
distance from the angle of the gape to the symphysis of 
the upper jaw, and it covers a depressed region that will be 
referred to, in its entirety, as the nasal-flap furrow. The term 
nasal groove is avoided, because that term (Nasenrinne), as 
employed by Gegenbaur, would seem to refer to a lateral and 
deeper portion, only, of the entire furrow, as will be later 
fully explained. Between the nasal flaps of opposite sides 
the edge of the upper lip of the fish is deeply re-entrant, 
exposing the teeth and a considerable portion of the upper jaw. 
A well-marked furrow separates this part of the upper lip 
from the underlying upper jaw, and may be called the upper 
labial sulcus. Laterally, on either side, this sulcus runs into 
the mesial (symphysial) edge of the corresponding nasal-flap 
furrow, and the posterior (oral) edge of the nasal flap of 
either side accordingly appears as a direct continuation of the 
upper lip. It is, however, not a continuation of that lip, the 
lip and its related sulcus being prolonged a certain distance 
along the floor of the nasal-flap furrow, internal to the nasal 
flap, and there gradually vanishing, as shown in PI. 6 , fig. 2. 
In the nasal flap, occupying approximately its entire- 
posterior (oral) half and extending mesially (symphysially) 
somewhat beyond the base of the flap into the subdermal 
tissues between the upper lip and the nasal capsule, lies the 
cartilage called by Gegenbaur the anterior upper labial. 
This so-called anterior upper labial of my specimen, like the 
corresponding one in Gegenbaur’s figure of Rai a vomer, 
lies external to the so-called posterior upper labial and farther 
from the symphysis of the upper jaw than that labial, but 
not definitely anterior to it. It is, however, not a labial 
cartilage, as will be later shown, but a cartilage developed 
strictly in supporting relations to the nasal flap. It can 
accordingly be called the nasal-flap cartilage, which will 
sufficiently distinguish it from the Nasenfliigelknorpel of 
Gegenbaur’s descriptions, which latter cartilage also in part 
supports the nasal flap and is the ala nasalis of certain. 
