78 ILLINOIS STATE ACADEMY OF SCIENCE 



CERTAIN DIFFERENCES BETWEEN TEXT-BOOK 

 EARTHWORMS AND REAL EARTHWORMS 



Frank Smith, University of Illinois 



This paper deals with earthworms of two quite differ- 

 ent kinds ; those that are found out of doors, in which I 

 have been interested for the past 30 years, and those that 

 are found in text-books, in which I have become inter- 

 ested more recently. During the 30 years that I have 

 been interested in the outdoor varieties I have spent 

 considerable time in collecting species in various parts 

 of the country and have examined a great many collec- 

 tions made by others. This has led to the discovery and 

 description of several new species not previously known, 

 and also has made clear that in almost any locality in the 

 United States there are likely to be several species that 

 may properly be called common. In most of the north- 

 ern and eastern states, the most abundant forms in 

 random collections brought into school rooms and labora- 

 tories would commonly include several species which are 

 also very common in Europe, and they have been intro- 

 duced wherever Europeans have settled and cultivated 

 the soil for many years. Introduced of course uninten- 

 tionally, they have thrived at the expense of indigenous 

 forms and to some extent have replaced them in the long 

 cultivated areas. In the Northern tier of states most 

 of the common species belong to the family Lumbricidae, 

 but include several different species of at least three 

 different genera. In the latitude of Illinois and farther 

 south, representatives of other families of earthworms 

 are abundant, and in many cases include the largest of 

 the specimens collected. Anatomically these are very 

 different from Lumbricidae. It is no more reasonable 

 to talk about "the common earthworm" than it would be 

 to talk about the common species of bird or the common 

 kind of fish. It is done in 29 of 47 text-books recently 

 examined. 



My interest in the text-book varieties of earthworms 

 has been increased recently as a result of a historical 

 study of the development of our knowledge of Lumbric- 

 idae in general. Lumbricus terrestris, which includes 



