4 SYMBRANCHIATE AND APODAL FISHES 
the branchial lamelle! rudimentary ; accessory breathing 
apparatus present, communicating with the gill-cavity ; 
branchiostegals six. Vertical fins rudimentary, reduced 
to more or less distinct folds of the skin; no paired fins. 
Vent situated in the posterior half of the length. Cranium 
short, not protecting the entire branchial apparatus. 
Shoulder-girdle not attached to the cranium by a bony 
process.” Vertebre—fide Giinther—106+65=171 
Fresh and brackish waters of the Punjab, extending 
to Bengal, Orissa, Assam, and Burmah (Day). Eastern 
Queensland. Monotypic. 
Since it is by means of these lamelle that the water, 
inhaled by all gill-bearing animals, whether larval or adult, 
is deoxygenated previous to its expulsion at the gill-openings, 
it will be easily understood that the absence or degradation 
of these organs, unless invalidated by some counter- 
balancing provision, is a matter of very serious moment to 
such an animal ; of so great moment, indeed, that if we were 
to take a freshly caught fish, and having carefully removed 
with a pair of scissors the delicate filaments which fringe 
the outer edge of the gill-arches, return it in all its seemingly 
pristine vigor to its native element, but few moments would 
elapse before it began to exhibit all the symptoms of 
asphyxiation, and death would shortly result. In the case 
of Amphipnous, however, the difficulty is met by the pro- 
vision of an accessory breathing apparatus, which com- 
municates directly with the gill-cavity and enables the fish 
to absorb atmospheric air by a simple act of suspiration ; 
its dependence on this organ is easily demonstrable by 
placing the fish in a glass jar, the mouth of which has been 
closed by a piece of gauze or fine wire netting ; if this be 
sunk beneath the surface so as to deny all access to the air, 
1Taylor (Gleanings in Science ii, p. 173), referring to these lamelle, 
informs us that the second gill-arch alone possesses them in the shape of 
‘a few long fibrils attached to the middle of the arch, and occupying but 
a very small extent of its surface,” while ‘‘the third supports in the place 
of lamine a thick and semitransparent tissue, which in large individuals of 
the species possesses a fringed or denticulated appearance on its edge.” 
2Giinther (Catal. Fish., viii, p. 13) describes the posttemporal as being 
“‘ very small and cartilaginous, continued into a muscle, which is attached 
to the skull.” 
