250 Dr. J. D. F. Gilchrist on the 
striking features, and may be considered first. The species 
of Psenes, which was found in rather deep water off the 
coast of Natal, seems to be new, and may be provisionally 
called P. natalensis for convenience, 
Psenes natalensis. 
The cesophageal pouches are conspicuous structures lying in 
the anterior end of the ccolom, apparently on the cesophagus, 
just behind the pharyngeal region. In a mature specimen of 
150 mm. they measure 16 mm. in length, or slightly larger 
than the diameter of the eye of the fish. They measure 7 mm. 
in vertical diameter. Unlike other cases, to be noted later, 
they he parallel with the alimentary tract, and do not extend 
below the level of its lower margin. Externally the whole 
5 
structure consists of a great thickening of the muscular layers 
of the splanchnopleure. Internally it is lined by the endo- 
derm, which expands out on each side dorso-laterally to form 
the pouches in which the “teeth”? are lodged. It is the 
nature of this endoderm and its tooth-like structures which is 
in question, but the relation of this whole structure to the 
branchial system may first be considered. It is in direct and 
intimate connection with the fifth branchial arch, the cerato- 
branchials of which are long and slender. They meet each 
other ventrally at a point, where they are supported at the 
end of the basal elements of the other arches. ‘There is a 
small slit separating the fourth and fifth arch, and on the 
Jatter there are about seven reduced gill-rakers. They pass 
upwards on each side of the anterior end of the cesophageal 
sacs, which they thus support. They are continued dorsally, 
as small epibranchial elements, directed forwards to very 
large well-calcified pharyngo-branchials, which are fused 
together to form a stout concave structure, in which the mass 
is firmly secured. The teeth on these upper pharyngeals are 
well developed, and form rounded patches, which lie in the 
anterior end of the cesophageal sacs, but do not penetrate 
further back, nor assume a lobed projecting form, as.they do 
in types noted below. Posterior to these teeth and in the sacs 
lie the cesophageal teeth. 
The sacs have thick walls, in which two muscular layers 
may be distinguished—an outer transverse layer and an inner 
longitudinal layer. On removing these, a somewhat remark- 
able appearance is presented, the whole of the exposed 
surface being covered with a series of what appears to be 
overlapping ‘scales , each measuring between 2 and 3mm, in 
diameter. On removing one of these it was found that 
