66 
fibres, of a sub-mucosa lying internal to these, and of a 
mucosa which is a simple columnar or cubical epithelium 
containing goblet cells. Four pyloric ceca (Ce. fig. 21) 
are present. Day (“‘ British Fishes,” vol. II., p. 26) states 
that only two are present, and Kyle apparently also agrees 
with this. When the intestine is distended with food 
these ceca may be obscured, but their presence may 
always be determined, and in the young fish (of 2 to 4 
inches long) they are usually particularly noticeable. One 
is present on the dorsal and proximal extremity of the 
duodenum, two on the ventral and proximal extremity, 
and one on the mid-ventral line about an inch distant (in 
large fishes) from the pylorus. This last caecum may be 
the largest of the four. They have a wide lumen freely 
communicating with that of the duodenum; their wall is 
very similar in structure except that the muscle layers 
may not be so distinct. 
The Pyloric Ceca are only seen in Teleostomatous 
fishes. The number present is very variable, none being 
found in the Sole and 191 having been counted in Scomber. 
There has been much discussion as to their morphology 
and function. At one time they were regarded as the 
homologues of the pancreas—an organ which was then 
supposed to be absent in Teleostomi. They have been 
regarded as absorptive organs and as accessory digestive 
glands. Mordecai from observations on Clupea sapidissima 
supposed that they served to store up reserve food material. 
In the fishes ascending rivers to spawn, when presumably 
no food was being taken, the ceca were found distended 
with a brownish mucus-like substance which was absent 
at other times in the year. Edinger supposed them to 
exercise an absorptive function. Wiedersheim also held 
this opinion, and correlated their presence with the 
absence of a spiral valve (a device for increasing the 
