LAWS OF ORGANIC DEVELOPMENT. 593 
glide of the Distegi, with which they are generally arranged, and, 
on the other, to the Blenniide. Some of the latter elongate the 
basal pectoral bones considerably, and lead to the Batrachide on 
the one side, where the number of these bones is increased, and 
on the other to the Pediculati, where the number’is diminished, 
To these groups the Anacanthini and Heterosomata are less allied. 
The third upper pharyngeal bone has already presented an in- 
crease of mass and use in the first orders of Physoclysti with ven- 
tral fins. Among the Percomorphi the same increase makes its 
appearance by little beginnings in some Sciaenide. It is quite 
noteworthy in most of the Carangide, a group whose separation 
from the Scombride by Günther is supported by this part of their 
organism. Through forms not now specified, approach to the 
Pharyngognathi is made. Here the pharyngeals are modified into 
a mill-like structure, which is least specialized in the rene iin: 
. and most so in the Scaride. 
. W. PuTNaM was not prepared to accept all the proar that 
were Kapok by Prof. Cope, some of which were somewhat r: At 
the same time, however, he regarded it as the nearest ea on a cor- 
rect classification of the fishes that had ever been made. The points of 
made, nor ina more unexpected manner. He thought Professor Cope 
had found the only means wei which one can with certainty distinguish a 
fish from a batrachia The way in which a number of the families had 
been grouped acai. he ai approved of, though some of the groups 
he thought still open to question. 
Tar Laws or Orcanic DEVELOPMENT. — By Pror. E. D. Cope. 
Tue discussion of this subject divides itself into two parts, viz.: 
a consideration of the proof that evolution of organic types, or de- 
scent with modification has taken place ; and, secondly, the inves- 
tigation of the laws in accordance with which this development 
has progressed 
I. ON THE PROOF FOR EVOLUTION. 
There are two modes of demonstration, both depending on di- 
rect observation. One of these has been successfully presented 
by Darwin. He has observed the origin of varieties in animals and 
plants, either in the domesticated or wild states, and has shown, 
what had been known to many, the lack of distinction in the 
grade of difference which separate varieties and species. But 
