262 II. LYNDHUKST DUKE. 



several specimens of this leech, aiul, ihouyh the results were 

 in the main negative, he found several animals infected with 

 a species of gregariue. Refei-eiice to the literature proved 

 the parasite to be identical witii a species briefly mentioned 

 by Bolsius in 1805 (2), and the subject of a more detailed 

 but still fragmentary paper in 1896 (3). Beyond a super- 

 ficial study carried on incidentally during his work on the 

 Glossosiphonia Bolsius seems to have paid no further 

 attention to the parasite, which remained unnoticed until 

 1900, when Castle (5), in an exhaustive treatise on the 

 N. American Rhynchobdellida) and their parasites, mentions 

 having observed the gregarine seen by Bolsius in about half 

 the specimens of Clepsine elongata which he examined. 

 He adds, however, that he only linds the animals in the 

 stomach diverticula, and never in the intestine or crop, as 

 indicated by Bolsius in his diagrams. Castle also mentions 

 encysted protozoa whicli he found in C. fuse a, and suggests 

 the possibility of their relationship to the form in G. com- 

 planata. The cysts he found in the muscle-layers oF the 

 body-wall, so that they jirobably have nothing to do with 

 the gregarine in question. 



Liihe (14) quotes the parasite as having been mentioned 

 by Bolsius, and suggests that it ]n-obably l)elongs to the 

 tricystid gregarines. 



The gregarine is thus a new and previously undescribed 

 form, for which I propose the name Metamera scliubergi.^ 



In the preparation of the sections and the study of the 

 living animal, during the last few weeks of my sta}- in Heidel- 

 berg, Professor Schuberg assisted me most kindly in every 

 way in his power; and it is due solely to him that I was able 

 to obtain Bolsius' principal pamphlet. My thanks are also 

 due to Geheimrat Prof. BUtschli, whose practical suggestions 

 I found of the greatest value. 



' The form whioli appears most closely allied as regards structure of 

 tlie trophozoite is E o li i n o m era. A study of the life-history, however, 

 has revealed points of difference which seem to wan-ant the creating of 

 a new genus for the form under consideration. 



