3/8 H. H. SWINNERTON. 
it are placed in the Haplomi. In the definition of this sub- 
order this sentence occurs:—“'The absence of the meso- 
coracoid arch distinguishes the Haplomi from the Malaco- 
pterygii, with which they are united by various authors.” 
This statement alone suffices to show that, apart from the 
absence of this arch, the Haplomi, at least as represented by 
the pike and Galaxias, are as primitive as the general run 
of Malacopterygii. If a list be made of the features which 
indicate lowly affinity among the latter, it will be seen that 
most, if not all, are found among the Haplomi. Again, in 
my paper on Cromeria (p.270) these words about Galaxias 
occur :—“ In some respects, e.g. forward extension of the 
cranial cavity, and the condition of the articular head of the 
hyomandibular, it is as lowly as, or even more lowly than, 
the salmon.” 
Whatever may be said about the classification of other 
Teleosts, it is generally acknowledged that the Ostariophysi 
form a natural group. ‘hough every conceivable modifica- 
tion of form and external character occurs amongst them, 
yet the mesocoracoid and the features associated with its 
presence remain constant. Again, among Malacopterygi 
there are forms which are extraordinarily specialised, but 
they nevertheless retain the mesocoracoid. ‘l'hese facts speak 
strongly for the stability of this structure. 
The absence of a mesocoracoid in Poly pterus was pointed 
out by Gegenbaur, and indicates the possibility that forms 
may have existed even among Holostei exhibiting the same 
peculiarity. Unfortunately fossils have as yet yielded no 
information on the primary pectoral girdle of these fishes. 
If there be any truth in the view just propounded, then we 
are able to recognise among ‘l'eleosts three distinct offshoots 
from the Holostean stock, viz. one including the Ostariophysi, 
another the Malacopterygii, and a third the Haplomi and all 
those teleosts with the same type of pectoral girdle. 
