III. 



Recent Progress in Our Knowledge of 

 Earthworms and their Allies. 



THE present paper is intended rather to appeal to those who desire 

 to be abreast of the latest information concerning a group of 

 worms already provided with a voluminous literature, than to aim 

 at a popular exposition of a subject hardly, perhaps, suited for such 

 treatment. For some reason or other, the Ohgochaeta in general 

 were, until a few years ago, perhaps, the least known group of any 

 among the invertebrates; and yet they are particularly suited for 

 investigation, and for many reasons. They are abundant, easily 

 found, and easy to manipulate by dissection or with the microtome. 

 Immense efforts are made yearly, at a large cost, to bring back 

 a few skins and horns which are intrinsically as a rule of no 

 interest at all, or of the very smallest importance. An infinitesimal 

 fraction of the necessary expense incurred in the shooting and pre- 

 servation of such material would supply many workers with abundant 

 matter for study if devoted to the collecting and proper preservation 

 of terrestrial and fresh-water invertebrates. To some extent this is 

 now being done ; and in the particular group upon which I report 

 here, several collections of some importance have recently been made. 

 Through the liberality of the Government Grant Committee of the 

 Royal Society, I was able to secure the assistance of Mr. F. Finn to 

 make collections in Zanzibar and Mombasa ; more recently still, the 

 Hamburg Museum sent out Dr. Michaelsen to South America, with 

 the result that a very large collection of Oligochaeta were brought 

 home by him, and most kindly entrusted to me for study. Besides, 

 the attention of naturalists travelling abroad with other aims has 

 been successfully directed to the importance of this group ; and in 

 consequence a good deal of material has dribbled in to various 

 Museums and individuals. Judging from the work of the last two or 

 three years, which I shall endeavour to summarise here, we appear to 

 be fairly advanced at the present moment in our knowledge of the 

 main structural features of the group, at any rate of the terrestrial 

 forms ; the aquatic Oligochaeta have been less collected, and are in a 

 backward state so far as information goes. I shall now try to make a 



