the late Professor BtidolpUi. 229 



and who have discovered and applied the principles for the ar 

 rangement of tliese, then Rudolphi's name would be rendered 

 imperishable by his investigations regarding the Entozoa? alone. 

 Linnajus had indicated only eleven species of intestinal worms 

 in the 12th edition of his Sijst. Nat. ; Gmelin, in the 13th edi- 

 tion, 299 ; Zeder, 391. Riidol phi's first great work on intes- 

 tinal worms, Entozoorum historia nattiralis, which appeared in 

 three volumes, between 1808 and 1810, before his removal to 

 Berlin, contains the description of 603, principally accurately 

 described species. He almost doubled that number by his own 

 personal observations, made more especially during a journey 

 to Italy, Avhich he undertook in 1817, chiefly for the prosecu- 

 tion of this subject ; by the communications of his intimate ' 

 friend Bremser ; and by the contributions sent from Brazil by 

 Von Olfers and Natterer. His Entozoorum Synopsis, published 

 in 1819, contains descriptions of 5ii9> accurately described, and 

 441 doubtful, altogether 993 species. 



Rudolphi made known many valuable observations on the 

 anatomy of intestinal worms ; and what he say^ in favour of 

 generatio cnquivoca, is still almost the only recorded expression 

 of opinion on which the defence of this doctrine can be made 

 to rest. Rudolphi's classification is still regarded as the most 

 approved one. Anatomy has here, it is true, made great pro- 

 gress under the guidance of Mehlis, but it has not authorized 

 us to arrange these so widely differing animals in already exist- 

 ing divisions of the remaining ones ; and hence, in the present 

 state of the science, the best plan would be simply to place 

 next one another the natural groups of the worms of fresh and 

 salt water, and of internal worms, so that the Annulata, the 

 Turbellaria of Elirenberg, the Nematoidea of Rudolphi, the 

 Trematoda of the same, and the Ta?nia, should stand next 

 one another, whether one of these anatomically different groups 

 should live within or without the animal body. One point in 

 which I cannot agree with Rudolphi is his separation of the 

 Cestoidca from the Cystica (Blasenwlirmer). It seems ren- 

 dered inadmissible by a more close examination of the Tetra- 

 hyncha and the Anthocephala, which are similar to them ; 

 these last were removed by Rudolphi to the Cystica, This di- 

 vision of the Cystica contains animals which are not more like 



