00 DAVIS I FISH-REMAINS IN THE COAL-MEASURES. 
the fish can live through the long dry season. The recurrence 
of rain, softening the "baked mud, is the signal for the semi- 
torpid mud fishes to emerge from their confinement : 
gradually the gills resume their function, and the swim- 
bladder is rendered useless for respiration and the purification 
of the blood until the next period of drought approaches. 
Prof. Jobert, in a paper published in a recent number of 
the Comptes Rendus,* describing researches " On the Aerial 
Respiration of some Brazilian Fishes inhabiting Fresh Water," 
described the pneumatic bladder of certain Sirenoid fish — the 
Erythrini — as containing internally a number of cells, which 
are richly provided with blood vessels, and connected with 
the oesophagus. By means of this arrangement, the fish is 
able to support aerial respiration for a long period. These 
observations were made on fresh specimens; and it was further 
found, that by obstructing the opening from this air-bladder 
to the atmosphere, the death of the fish ensued. These fishes, 
which inhabit the Upper Amazon, may be frequently seen 
travelling from a dried-up pool, across the country in search 
of more congenial quarters ; and during such excursions, the 
lung-like air-bladder serves all the purposes of respiration. 
The report concludes, "Nous voyons done que le voyage 
de M. Jobert dans le vallee de la Haute- Amazone a deja 
fourni a la zoologie physiologique des faits tres-interessants 
qui etablissent de nouveaux liens entre les poissons ordinaires, 
les Lepidosiriens et les Batraciens perennibranches, qui 
possedent a la fois des branchies et des poumons ordinaires. 
Les observations de M. Jobert sur la respiration intestinale 
des Callichthys ont non moins d'importance." 
So far as the imperfect remains of the Ccelacanthoid 
fishes enable one to form an opinion, they appear to have 
existed under very similar circumstances during the deposi- 
* Comptes Rmdus, April 15th, 1878, p. 935. 
