FISHES—REGAN. 
The supposed relationships of the Nototheniiform families and of the cenera of 
Ss 
the Bovichthyidae are shown by the following diagram :— 
Chaenichthyidae Bathydraconidae 
Nototheniidae 
| Bovichthys 
Cottoperc: 
Pseudaphritis 
FA 
Bovichthyidae. 
In summarising the distribution of the Nototheniiformes the Bovichthyidae, the 
most generalised family, may be considered first. Psewdaphritis most nearly represents 
the prototype of the whole group and is the only genus peculiar to the South 
Temperate Zone ; but the single species also differs from other fishes of the family in 
that it is chiefly, or perhaps entirely, fluviatile. It may perhaps be regarded as a 
relict form, analogous to the Galaxias of New Caledonia, dating from a time when the 
seas of Australia were colder. The related Cottoperca is marine and is confined to the 
Magellan District, whilst Bovichthys, which seems to be Cottoperca specialised, is 
principally South Temperate, but is Subantarctic also in the Antipodes District. 
The remaining families include 22 genera; one (/leginops) is monotypic and 
occurs in the Magellan, Chilean and Argentine Districts; the rest are Antarctic, 
16 peculiar to the Glacial District, one peculiar to the Kerguelen District, and four 
found also in the Subantarctic Zone. Of these last, two (Dissostichus, Harpagifer) 
are monotypic, the third (Champsocephalus) has only two species, and the fourth is the 
large genus Notothenia, well represented in both Antarctic and Subantarctic Zones. 
The species of Notothenia form five natural groups :— 
(1) the tessellata group, comprising the first eight species in the list and confined 
to the Magellan District ; these have the interorbital region rather broad, the 
upper surface of the head except the snout, and its sides except the praeorbital 
fully scaled. 
(2) the sguamifrons group, including only NV. squamifrons from Kerguelen and 
N. larseni from Graham Land and South Georgia; distinguished from 
the preceding by the narrow interorbital region and the scaly snout and 
praeorbital. 
(3) the acuta group, including the next five species, all belonging to the Antarctic 
