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 Jlranea, 

 &c. which are always accessible in every season of the 

 year, and all the varieties of some species, .such as cams 

 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 con* 

 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 

 een given by other naturalists, whenever it is ascer- 

 tained. 



