938 
the slave of neither prejudice nor precon- 
ception and abandons the accepted truth of 
yesterday if only it be the demonstrated 
error of to-day. It places no premium upon 
personal prerogative, and extends no recog- 
nition to individual authority. It makes 
no proclamation of completeness, no pre- 
tension to sufficiency. It recognizes that 
truth is undergoing progressive revelation, 
not ending to-day, but continuing through 
the ages. It yields its plaudits to achieve- 
ment, and recognizes that he is the greatest 
among men who reveals the most of truth 
unto men. It greets asa friend him who 
thinks, though he think error, for, thinking, 
he may think truth and thereby add to the 
common fund. It heeds all things, examines 
all things, judges all things. 
To you, the exponents of this new school, 
of this new generation, of this new century ; 
to you, representatives of the Democracy of 
Science ; to you, citizens of the Republic of 
Letters, I extend greetings; and here, in 
our parliament assembled, here, where our 
will is supreme, I this day invoke upon our 
deliberations the spirit of liberty, the spirit 
of courage, the spirit of progress, the spirit 
of truth. 
CHaries A. L. REEp. 
VARIATIONS IN THE APICAL PLATES 
OF ARBACIA PUNCTULATA FROM 
WOOD'S HOLL, MASS. 
THE object of this note is to call the at- 
tention of naturalists to three points of 
variation in the apical system of the com- 
mon eastern sea-urchin, Arbacia punctulata. 
The variations may be already known, but 
I had not noticed them till a year ago, and 
have never seen any mention of them in 
print. The observations are based on the 
study of sixty-three dry specimens sent me 
for class use from Wood’s Holl, Massa- 
chusetts, by Mr. F. W. Walmsley. The 
different plates can be seen very readily 
if, after removing the spines, the surface be 
SCIENCE. 
[N. S. Vou. XIII. No. 337. 
washed and gently brushed with a weak 
solution of caustic potash and then dried. 
Great care is necessary in handling the 
anal plates or they will fall out. The 
drawings were all made under a camera 
lucida, magnified four diameters and then 
reduced one-third. The views are all 
placed in a similar position, 7. e., the an- 
terior radius (as defined by Lang’s ‘ Text- 
Book of Comparative Anatomy’) is with the 
madreporic plate in the right anterior inter- 
radius. The views are arranged so thatall 
those having four anal plates are in the 
center and those with three or five are 
below or above. This figure is a view of the 
LD AR? 
arrangement of apical plates most fre- 
quently found, the ‘mode,’ as it is called 
by recent writers on variation. It was 
selected to represent forty-five cases with 
