from the GNU version of the Collaborative International Dictionary of English
- n.pl. A group of ganoid fishes, including the living genera Ceratodus and Lepidosiren, which present the closest approximation to the Amphibia. The air bladder acts as a lung, and the nostrils open inside the mouth. See ceratodus, and Illustration in Appendix.
from The Century Dictionary and Cyclopedia
- A subclass of fishes, by some considered to be a peculiar class of vertebrates intermediate between fishes and batrachians, and by others an order of fishes (by some ranked as a suborder of ganoid fishes), containing the lung-fishes of the genera Lepidosiren and Protopterus (Dipneumona) and Ceratodus (Monopneumona), and many extinct relatives.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. bony fishes of the southern hemisphere that breathe by a modified air bladder as well as gills; sometimes classified as an order of Crossopterygii
Sorry, no etymologies found.
Silurian and the coal measures, we find very plentiful remains of certain fish called the dipnoi, of which group three genera still survive; they display, in numberless features of their anatomy, transitional characters between true fish and amphibia.
Of the older dipnoi (Paladipneusta) we have now only one specimen, the remarkable Ceratodus of East Australia; its amphiblastic gastrulation has been recently explained by Richard Semon (cf. Chapter 2.21).
So again, while the group of fishes, termed ganoids, is, at the present time, so distinct from that of the dipnoi, or mudfishes, that they have been reckoned as distinct orders, the Devonian strata present us with forms of which it is impossible to say with certainty whether they are dipnoi or whether they are ganoids.
5Google “Diabolepis and its relationship to dipnoi”