(Esophageal Teeth of the Stromateide. 253 
supported mainly by the epibranchial and pharyngo-branchials 
of the fourth gill-arch. The toothed upper pharyngeals are 
not rounded patches, but are in the form of two ridges which 
project backwards and end in pointed free extremities pro- 
jecting into the opening of each sac. There are a few reduced 
anterior gill-rakers on the fifth branchial arch, and the 
opening of the cesophageal pouch is immediately behind the 
gill-arch, so that there is a more apparent transition between 
the gill-rakers and the cesophageal teeth, which might there- 
fore be readily interpreted as the posterior gill-rakers of the 
fifth branchial arch. These teeth are apparently of the same 
nature’as in the last case. There is a marked difference, 
however, in their basal expansion, for they are firmly fixed 
in the muscular wall of the pouch, not bya circular scale-like 
structure, but by a number of root-like processes, which are 
more or less curved at their pointed extremities (text-fig. 2). 
Psenes (Atimostoma, Smith; Cubiceps, Gtinther) capensis. 
The cesophageal sacs of this species do not, as in P. nata- 
lensis, lie parallel with the cesophagus, but more or less across 
it, following the general contour of the branchial arches. 
They thus project below the level of the cesophagus. They 
are closer to the branchial arches, and are mainly supported 
by the fourth. The most noteworthy difference is the 
greater development of the toothed upper pharyngeals. 
These, in the first arch, are poorly developed, and have 
no teeth, those of the second have a small patch of teeth, 
those of the third are well developed, and those of the 
fourth extend backwards as large toothed lobes into the 
cesophagus, past the openings of the two cesophageal pouches. 
The pouches are provided with rounded toothed lobes or 
papilla similar to the pharyngo-branchials of the fourth 
arch. The long horny processes resembling gill-rakers are 
entirely absent in this species, and the inner lining of the 
cesophageal sacs seems to be entirely derived from a backward 
extension of the tooth-bearing epithelium of the superior 
pharyngeals. This epithelium can readily be distinguished 
from the cesophageal epithelium, which in this and some other 
species of the Stromateide is characterized by longitudinal 
foldings. These extend forward on the floor of the cesophagus 
between the sacs, and pass over the lip of the sac but not 
into it. 
Nomeus gronovit. 
In this fish the cesophageal sacs follow still more closely 
