40 
MR. a. SIM ON THE OCCURRENCE ETC. OP 
of dentition, Centronotus has a single row of conical teeth in both 
jaws, becoming shorter as they approach the angle of the mouth ; 
sometimes there exist a few irregularly set teeth in the upper jaw 
in addition to the regular row ; several strong teeth on the 
vomer ; four patches, two on each side, of irregularly set upper 
pharyngeal teeth, and two long patches below, also set irregu- 
larly. On the other hand, Lumpenus is furnished in the upper 
jaw with numerous irregularly set teeth, the outer ones being 
conical, the others sharp-pointed, and all decreasing in length as 
they approach the angle of the mouth. The lower jaw is set with 
one, sometimes two rows of long incurved, rather sharp teeth, 
not of uniform length, and all becoming shorter laterally ; none 
on the vomer or tongue. There are two irregularly set patches 
of upper pharyngeal teeth, each point of which is finely tinged 
with yellow ; and four lower pharyngeals forming two sides of a 
triangle set confusedly, and without the yellow colour of the 
upper ones. In the number of vertebrae, Centronotus outnumbers 
Lumpenus by 3, the latter having 80 and the former 83. 
But the greatest departure which Centronotus makes from 
Lumpenus is in the form of the stomach and intestines. As will 
be seen by the accompanying figures, the intestines of Centronotus 
in some cases show little change in the stomach from the intestines 
proper ; that is, there is no very distinct line of demarcation 
between them ; presenting more or less the form of a simple 
tube and are devoid of caeca. I have said in some cases. This 
will be best understood by referring to figs. 1 and 2, both of 
which represent the intestines of Centronotus, both drawn from 
specimens caught by myself and while the intestines lay in situ. 
This is a change in the internal arrangement of a species I have 
never before observed carried to such a length, although the indi- 
viduals of no species have the intestines formed or laid exactly 
alike. The result of my investigation goes to show that fig. 1, 
or something much like it, is the most usual arrangement to be 
met with in Centronotus gunnellus. On the other hand, Lum- 
penus has what may be called a properly developed stomach, 
marked off from the intestines by its two caecal appendages, and 
the intestinal track forms several convolutions in its course. 
With reference to the caeca in Lumpenus, I find they differ 
much in length in different individuals, even although these indi- 
viduals are of themselves the same size. In some examples 
