30 
over the winter, Walshii coming out earlier than Telamonides. 
The former produces broods of both types by the early sum- 
mer, and of Marcellus in the later summer and fall. Telamonides 
produces Marcellus in the later summer, and its own type in 
the spring, (some chrysalids hatching out promptly, and some 
living over till the next year). Marcellus develops its own 
type the same season, while the chrysalids that go over till 
spring, appear as the early brood of Walshii and the some- 
what later brood of Zelamonides. <A large series of careful 
observations has placed these facts beyond further question, 
seemingly; and American entomology is under much obliga- 
tion to Mr. Edwards for thus unravelling some of the most 
perplexed relations of our species and varieties, and giving us 
a clear insight into their interesting circles of change. It is 
to be hoped that he will be able to carry on his observations, 
and yet further elucidate our nomenclature, not only, but our 
ideas. 
The PRESIDENT exhibited specimens of Celacanthus elegans, 
Newb., from tie coal-measures of Linton, Ohio, and made 
some remarks upon the structure and history of the small 
and peculiar group of fishes represented by this genus. It is 
customary to meet with the statement, that all the ancient 
fishes possessed the so-called heterocercal tail, in which the 
vertebral column is prolonged into the upper lobe of the 
caudal fin. In the Carboniferous age, however, this group 
of Ccelacanth ganoids appears, having a tail-structure quite 
different from the heterocercal, and to some extent resembling 
that found in our modern fishes, in which the tail-fin is equally 
developed above and below the end of the spinal column. 
There is, however, a marked difference from the modern 
type, in that the Coelacanths have the vertebral column not 
terminating abruptly, but prolonged through the caudal fin, 
and carrying a smaller secondary fin at its absolute tip. 
The genus Celacanthus, represented by several species 
from the Carboniferous and later rocks of England and the 
Continent, originally described by Agassiz, is now found to 
