NATURAL SCIENCES OF PHILADELPHIA. 110 



Kingdom Protozoa of Professor Owen, and other large groups, as above desig- 

 nated. 



The evident and insurmountable difficulty in arranging well known groups of 

 inferior organization on the preconceived idea of the existence of two king- 

 doms only, and that tho-e inferior groups must belong to one or the other, 

 has led several naturalists into suggestions and propositions relating to a 

 third kingdom, or other group of high grade. Usually, and, in fact, in nearly 

 all instances, those suggestions take the form of mere intimations, or rather 

 doubtfully expressed opinions that a third group is possible, and in the large 

 majority of cases the intimation relates to the supposed existence of forms 

 and groups intermediate between animals and vegetables. Occasionally doubts 

 are clearly stated as to the propriety of regarding some specified forms as be- 

 longing to either of the two great groups commonly received, and in a few 

 cases the division of organized nature into three great primary groups, or 

 kingdoms, has been proposed and presented in detail. 



The proposition of M. Bory de Saint Vincent is one of the most clearly de- 

 fined. That distinguished naturalist, in " Dictionnaire Classique D'Histoire 

 Naturelle," (vol. viii. p. 2-16,)* establishes an additional intermediate king- 

 dom which he denominates " Regne Psychodiaire," and gives his conclusions 

 on the existence of this third, but intermediate, kingdom in a very lucid and 

 satisfactory manner, and with entirely judicious and proper minuteness of detail 

 on such an important proposition. His views are mainly based on the fact that 

 some organisms assume, at periods or stages of their existence, characters of 

 both animals and vegetables, or, as he expresses himself, even of animals 

 and minerals. He says : " Tous ces etres qui sont a la fois, des Animaux, 

 des Plantes ou des Mineraux, et qui ne peuvent consequemment rentrer d'une 

 maniere exclusive dans l'uu des trois regnes adoptes jusqu'ici, ne doivent-ils 

 pas former un regne nouveau dont plusieurs naturalistes out deja reclame 

 l'etablissement, et que nous avons le premier propose de fonder sous le nom 

 de Psychodiaire." In volume xiv. of the same work, (Dictionnaire Clas- 

 sique,) M. de Saint Vincent fully defines and expresses his conclusions in re- 

 lation to his proposed new kingdom, (p. 329). He divides it into three classes, 

 to which he applies the names " les Ichnozoaires, les Phytozoaires et les Litho- 

 zoaries," the first of which groups embraces "les Polypes nus de Cuvier," 

 and the second and third, the groups of organisms previously known as 

 Zoophytes and Lithophytes as his proposed names indicate. Mainly the king- 

 dom Psychodiaire of M. de Saint Vincent is identical with the Class Protozoa, 

 of Prof. Goldfuss and subsequent authors, the difference being essentially that 

 the former regards his proposed kingdom as a great group, equal in grade to 

 the kingdoms Animalia and Vegetabilia, and intermediate between the two, 

 while 'the latter regards his group only as a class of the Animal kingdom, and 

 the first and least complex in organization of his eleven divisions of the 

 grade of classes. 



This is, so far as our knowledge extends, the first arrangement or classifi- 

 casion in Natural History in which three primary groups of organized beings 

 are distinctly proposed. M. de Saint Vincent also proposes an additional in- 

 organic kingdom, which he names the " Regne Ethere." 



In an article in the "Edinburgh New PhilosophicalJournal," vol. xii. new 

 series (p. 216,) "On the distinctions of a Plant and an Animal, and on a 

 fourth kingdom of Nature," by Mr. John Hogg, a British Naturalist, who has 

 devoted much attention to the lower organisms, that gentleman proposes the 

 name " Primi<jenum' n for the group established by Professor Owen, under the 

 name " Protozoa." He does not, however, propose any change in the classes, 



*The date on the title page of this volume is 1S25, but it is quoted and referred to by M. de Saint 

 Vincent himself in Encyclopedia Methodique, supplementary volume on ' Hist. Nat. des 

 Zoophytes," which is dated 1S24 (p. 057). His views are niu.it fully expressed, subsequently, in 

 Diet. Class., vol. xiv. p. 329 (1828). 



1863.] ' 



