134 _ ZOOLOGICAL SPECIES. 
without assistance, his life must be protracted to a very 
advanced period to afford him time to complete the work. 
But if every student will contribute his mite, by sending 
Mr. Say duplicates of all undiscribed species, we shall 
probably be in possession of a system, very nearly com- 
_ plete, in a few years. 
In writing descriptions, be particular to set down the 
day of the month when collected, in what particular 
situation found, and every thing known of the habits 
and instincts. Such as under stones, under bark of 
trees, in stagnant water, in running water, under the 
skin of animals, making a vertical web, digging holes in 
the earth, catching insects, &c. &c. 
Though but few species are described in this book, 
they will be found sufficient for a course of exercises. 
All the known species in some genera, such as Aranea,; 
&c. which are always accessible in every season of the 
year, and all the varieties of some species, such as canis 
familiaris, are described, for the purpose of exercising 
students in the various kinds of analysis. 
The following exercise is proposed for all students in 
Zoology, until a system of American Zoology shall be pub 
lished, embracing all the species. 
After finding the generic name, and searching for the - 
specific name without success, for want of a system cons 
taining a description; give the specimen a specific name, 
derived from Latin or Greek, expressive of its most 
striking peculiarity. To this name annex a full descrip- 
tion ; leaving out all that is contained in the generic de- 
scription. This name is to be changed to that which has 
been given by other naturalists, whenever it is ascer- 
tained, 
