10 ILLINOIS BIOLOGICAL MONOGRAPHS [228 



HISTORICAL DATA 



More than a century ago the first of the Monostomata were described. 

 Since that time many helminthologists have contributed to the study of 

 this group. Most notable of the older authors are Zeder, Rudolphi, von 

 Siebold, Van Beneden and Diesing. In more recent times Brandes, Stos- 

 sich, Looss, Liihe, Monticelli, Kossack and Odhner have contributed 

 materially to our knowledge of the European forms. 



Apart from the work of Goeze (1782) who described two species which 

 he believed to have only one sucker and that of Schrank (1788) which was 

 a mere catalogue of species, Zeder (1800, 1803) was the first to establish 

 this group. In 1800 he created the genus Monostoma based on five species; 

 Monostoma ocreatum, and Monostoma bombynae which have since been 

 removed to the distomes; Monostoma verriicosum a Notocotylid; and 

 Monostoma prismaticum and Monostoma mutabile which are now trans- 

 ferred to the genus Cyclocoelum. Rudolphi in his Synopsis Entozoorum 

 served in the early organization of the group. While a number of species 

 were imperfectly known at this time it was not until the work of von 

 Siebold (1835) was published that the anatomy of these worms was clearly 

 understood. In this work the author gave a good description of Monostoma 

 mutabile Zeder along with the early stages of the life history as shown in 

 the development of the egg before it is discharged from the uterus. Diesing 

 (1850) reorganized the genus including all species described up to this 

 time. Following this Van Beneden (1861) reviewed the anatomy of 

 Monostomum mutabile and added a description of the anatomy of Mono- 

 stomum verrticosum Frdlich with a study and description of a cercaria which 

 he believed to be the larval form of this species. The next important 

 contributions to the knowledge of this group were those of Monticelli 

 (1892) in which he gave a complete account of the genus Notocotyle Dies- 

 ing and in a second paper in the same year a similar account of Monosto- 

 mum cymhium Diesing. Closely following these was the Revision of Brandes 

 (1892) in which he proposed the new genus Cyclocoelum to include Mono- 

 stomum mutabile, M.flavum, M. arcuatum, M. tringae and M. elUpticiim. 



In more recent time the work of Stossich (1902), Odhner (1905, 1907) 

 and Kossack (1911) stands out as important contributions to the knowl- 

 edge of this group. Looss and Liihe have likewise had a share in the 

 organization of the group as a unit. The most recent European work on 

 members of this group is that of Jegen (1917) in which he presents data on 

 the life history and relationship of Collyriclum faba Bremser. 



