92 THE AMERICAN NATURALIST. (Vor: XXXIX. 
from the chondrostean ganoids, through the holostean ganoids (Aspi- 
dorhynchus, Lepisosteus, Amia, etc.) which he regards as teleosts. 
On the other hand, the Crossopterygii, likewise descended from 
Chondrostei, have given rise to Dipneusti (dipnoans) and also to 
Placodermi. This latter group includes both Ostracophores and 
Arthrodires. The Heterostraci are excluded from this group, being 
regarded as armored sharks. 
The fact that paleontology does not bear out this view is dis- 
missed with the statement that these conclusions *are in accordance 
with the morphological evidence, which is clearly and sufficiently 
complete, whilst the geological record is and must be from the nature: 
of the case very incomplete." 
The close resemblance between the basal structures of the paired 
and the unpaired fins in the Chinese Paddle-fish (Psephurus gladius) 
is one of the important pieces of evidence in favor of the primitive 
nature of the Chondrostei, and in favor of the origin of all fins alike 
from folds of skin. 
The conclusions of Mr. Regan are thus summed up: 
1. The Chondrostei are the most generalized Teleostomi. 
2. The Crossopterygii differ from them in the lobate pectoral fin 
and in the larger paired gular plates. 
3. The placoderms (Coccosteidæ, Asterolepidæ, Cephalaspidæ) 
are a natural group not related to the Heterostraci, which are Chon- 
dropterygii. They may probably be regarded as armored primitive | 
Crossopterygii, this view being most in accordance with the arrange- 
ment of the cranial roof bones in Coccosteus, the structure of the 
ventral fin in Coccosteus, and the structure of the pectoral limb in 
Asterolepidæ (which structure he regards as a true pectoral fin). 
4. The Dipneusti probably originated from more specialized 
Crossopterygii, e. g., from the neighborhood of the Holoptychidæ. 
5. The Teleostei differ in so many respects from the Chondrostei 
that they should rank as an order in which the Holostei are 
included. 
This view of the case is original and suggestive, but so far as the 
major premise (No. ı above) is concerned, most naturalists will find 
it unconvincing. 
Mr. Regan discusses the genus Lichia of Cuvier, dividing it into 
two genera, Lichia (Amia) and Campogramma Regan (V adigo). 
Lichia glauca he refers to the genus Trachinotus. The gaff-top-sail 
Pampano, also called Zrachinotus glaucus, a name of later date, is 
deprived of its name by the intrusion into the same genus of an 
