Bd. V: 6) 
THE FISHES OF THE SWEDISH SOUTH POLAR EXPEDITION. 
55 
Short notes on the morphology of the digestive system of 
Not ot hen ii dee. 
The shape and arrangement of the intestinal organs is rather similar in all the 
members of this family examined. 
The liver is often large. Its main mass lies to the left, constituting a very large 
and long lobe, which often as in Trematomus hansoni georgianus extends back- 
wards almost to a level with the anal opening. The shape of the liver of this fish 
is represented in fig. 2 in ventral aspect. The meeian portion often forms one or 
two short lobes and the right portion is represented by 
narrow lobe quite anteriorly. This organ seems, how- 
ever, to be subject to a considerable individual variation 
as in some specimens of this same fish the viscera were 
much more broadly covered by the liver than in the one 
figured. The same organ of other members of this fa- 
mily has about the same shape although the large left 
lobe does not extend quite so far back, almost two 
thirds of the distance to the anal opening or more in 
Champsocephalus gunnari, Notothenia gibberifrons and 
tessellata, somewhat less still in Notothenia macrocephala 
marmor at a, coriiceps etc. and Harpagifer. In Para- 
chœnichthys the liver is very large extending two 
thirds to the anus and the mass corresponding to the 
left lobe expands also beyond the median line towards 
the right side. 
The size of the ventricle is considerable and when 
it is filled with food it has been found to extend all way 
to the posterior end of the abdominal cavity in several different species belonging 
to different genera of Nototheniidœ. Already this faculty of dilatation indicates that 
these fishes possess ventricles of the cæcal type, to use Owen’s nomenclature. In 
Notothenia gibberifrons this type is perhaps least differentiated of the species exa- 
mined in this respect. Its ventricle has when moderately expanded the cardiac and 
fundus-portivns not much wider than the pylorus-portion. The latter is directed 
forwards. In other species of Notothenia ( tessellata , coriieeps , macroceph. manno- 
rata ) the general arrangement is the same, but the fundus-portion forms a larger 
cul de sac. In Trematomus hansoni georgianus the pylorus-portion branches of at 
ringht angle and the cæcal type is thus more differentiated, as fig. 3 shows. In 
Champsocephalus gunnari the fundus-portion forms a still wider and larger cul de 
