256 Wachsmuth and Springer—Silurian Crinoids. 
der the firstname. He objects to our definition of the characters 
of the former, to our rectification of the latter, and to our refer- 
ence of species thereto. He also intimates that we have taken 
unwarrantable liberties with Billings’ genus, and been guilty 
of a lack of proper respect for the work of its founder. 
We have given to the remarks of Mr. Miller the considera- 
tion that is due to the observations of a gentleman of acknowl- 
edged learning, and whose researches in the literature of this 
branch of Natural Science have lightened the labors, and merited 
the thanks of every American Paleontologist; and have re 
viewed the species referred to the two genera in question with 
the aid of somewhat better material, as to some of them, than 
r 
torily than before; one of which was represented by the two 
species described by Billings as Reteocrinus, but with a miscon- 
a of their true characters. 
t may probably be said with justice, that in this case, as 
perhaps in some others, we have adhered in our diagnosis of 
generic characters rather closely to the particular form which 
we regard as typical, and have not in express terms indicate 
the limits to which variations of these characters may and do 
extend. That modifications of characters and departures from 
the typical form in various directions are to be expected with- 
in the limits of every genus, is a fact which we have always 
ES at ae ee 
