172 Friend : The Annelid Fauna of Worcestershire. 



entitled ' Revision e dei Lumhricidi,' to which every later student 

 owes an immense debt of gratitude. He pointed out that 

 while the different species of Earthworms may be readily identi- 

 fied by external characters alone, it is absolutely necessary to 

 study the internal organs to obtain a satisfactory classification. 

 Availing himself of the work of Eisen, Oerley, and others, he 

 split up the old genus AUolobophora (Eisen) into four groups. 

 After having rejected Dendrohaena for a time, he re-adopted it. 

 together with Oerley's term Octolasion, and added a new term 

 Notogama. It was found that, not only did the spermathecae 

 vary in number, but that they were located in different segments, 

 and opened in different directions ; while the vesicles also 

 varied in number, and in their relation to other essential organs. 

 Here, again, some of the points of difference were trifling, 

 if considered by themselves, but as time went by, it was found 

 that their cumulative character rendered the division of the 

 old genus imperative. Rosa's division was an advance upon 

 Eisen 's, and may be summarised thus : — 



1. Allolobophora — Vesiculae seminalis four pairs, testes 

 and funnels free, spermathecae opening in a line with the dorsal 

 setae. Setae geminate (or strictly paired). Colour variable. 



2. Dendrobaena — Vesiculae seminalis three pairs, testes 

 and funnels free, spermathecae opening in the direction of setae 

 3 or 4. Setae more or less distant ; purple coloured dorsally. 



3. Octolasion — Vesiculae seminalis four pairs, with four 

 capsules enclosing testes and funnels. Spermathecae opening 

 in the direction of the third seta. Setae distant, i.e., in eight 

 rows. 



4. Notogama — Vesiculae seminalis four pairs, testes and 

 funnels free, spermathecae opening near the median dorsal 

 line, setae either paired or in separate rows more or less distant ; 

 with or without pigmented zones on the dorsal surface. 



It is not necessary to deal with Oerley's classification. Some 

 of his terms, svich as Aporrectodea, have never been accepted, 

 though he was perhaps the first to suggest that the worms 

 whose tubercula pubertatis fall on alternate segments (as A. 

 chlorotica Savigny) should be separated from those in which they 

 form a continuous band. Octolasion (which Dr. de Ribaucourt 

 persistently spells Octalosion), has proved a useful term, and 

 is at the present time in vogue for certain species whose setae 

 are in eight rows. 



So long ago as 1845 Hoffmeister, who did splendid work 



Naturalist, 



