Cuap. II. LAYING OF THE EGGS. 495 
tance of correct dates and labels for every specimen. A most valuable collection may 
be made almost useless from want of attention to these details; whereas if every 
contributor to public or private museums would furnish precise information respect- 
ing the origin of the specimens he has collected, he would confer a real service 
upon science. Every specimen should be marked with the exact date and place 
at which it was found, otherwise it may be worthless for purposes of comparison 
with other specimens. It would not be difficult to show how important are 
these apparently triflme details. One example may suffice. Thousands of speci- 
PI g I 
mens of the Blind Fish of the Mammoth Cave have been brought home by vis- 
itors of that interesting locality, and are now scattered throughout the country. 
They have been examined again and again by naturalists; but to this day the 
fo) oO 
period at which they spawn has remamed unknown, even though eggs have been 
Had the collect- 
ors marked the time at which such specimens were caught, we should know, from 
observed in their ovary in an advanced state of development. 
that observation alone, what is their spawning season. And so it is with every 
kind of specimens ; without accurate dates we shall learn little from them, of what 
they might teach us, if they were properly labelled. 
With reference to the subject of Turtles, now under consideration, the cause of 
the discrepancy between the knowledge of the learned and of the field observer 
lies in the circumstance, that, in the Old World, no Turtles are to be found in 
the immediate vicinity of the great centres of study, and that most of the infor- 
mation collected upon these animals has been recorded from the casual observations 
of travellers. In this estimation I do not, of course, include the investigations 
made upon their structure, which may very well be traced and completed from 
specimens preserved in alcohol; as every naturalist knows that one of the master- 
fresh-waterTurtleof Eastern Europe! Rathke has also published as full an 
Embryology of that species*—as-the circumstances under which it was prepared 
would allow, a monograph, which, with his many other embryological researches, has 
won for him a place in that constellation of emiment writers whose studies have 
made Embryology what it now is. But it is felt, on almost every page of his work, 
that he labored under a scarcity of materials which constantly impeded his pro- 
ress. 
g As I can plead no such difficulties for the imperfections which my present 
less than ten years, be made worthy of a careful ex- 
amination by even the most critical professional natu- 
ralists, and would afford to the teachers and pupils a 
source of ever new interest in their walks, and of ever 
increasing extension of their knowledge, and ability to 
observe. In Massachusetts a very good beginning 
has already been made, in several schools; and most 
successfully by Mr. J. W. P. Jenks, in Middleboro’. 
? Bosanus (L), Anatome Testudinis Europe, 
Vilna and Leip., fig. 1819-21, vol. fol. 
? Raruke (HH), Ueber die 
Schildkréten, Braunschweig, 1848, 1 vol. 4to. 
<ntwickelung der 
