84 



Hitchcock's anatomy 



186. Classification of Animals. — The highest and most 

 competent authorities differ widely in their attempts to classify 

 the Animal Kingdom ; that is, to divide it into smaller groups, 

 which are Sub-Kingdoms or Provinces, Classes, Orders, Fa- 

 milies, Genera, and Species. We have no room, had we the 

 ability, to decide these difficult questions. There is, how- 

 ever, a general acquiescence in the principle first introduced 

 by Cuvier, that animals w r ere created on four great types or 

 plans, which he calls Vertebrata, Articulata, Mollusca, and 

 Radiata. The discrepancy lies chiefly in the subdivisions of 

 these leading groups. We shall merely present the classifi- 

 cations of two of the most eminent living anatomists and zoolo- 

 gists — Professor Louis Agassiz of Cambridge, and Sir Richard 

 Owen of London — not attempting to decide between them. 



187. Agassiz divides the whole animal kingdom into four great branches, 

 the same as those named above. The Yertebrata he divides into eight 

 classes: 1, The Myzontes, subdivided into two orders; 2, Fishes proper, 

 into two orders ; 3, Ganoids, into three orders ; 4, Selachians, into three or- 

 ders; 5, Amphibians, into three orders; 6, Reptiles, into four orders; 

 Birds, into four orders ; 8, Mammalia, into three orders. 



The Branch Articulata he divides into three classes: 1, Worms, with three 

 orders ; 2, Crustacea, with four orders ; 3, Insects, with three orders. 



The Branch Mollusca he divides into three classes: 1, Acephala, with 

 four orders; 2, Gasteropoda, with three orders; 3, Cephalopoda, with two 

 orders. 



The Branch Radiata he divides into three classes: 1, Polypi, with two 

 orders; 2, Acalephaj, with three orders; 3 Echinoderms, with four orders. 



188. Owen calls the above-named four divisions of the Animal Kingdom, 

 Provinces. The Province Vertebrata he subdivides into four classes : 1, Mam- 

 malia, with fifteen orders ; 2, Aves, or Birds ; 3, Reptilia, with fifteen orders ; 

 4, Fishes, with eleven orders. His fifteen orders of Mammalia are : 1, Mono- 

 tremata; 2, Marsupialia; 3, Rodentia; 4, Insectivora; 5, Cheiroptera; 6, 

 Bruta; 7, Cetacea ; 8, Sirenia; 9, Toxodontia; 10, Proboscidea; 11, Peris- 

 sodactyla; 12, Artiodactyla ; 13, Carnivora; 14, Quadrumana; 15, Bimana. 



The Province Articulata he divides into six classes : 1, Arachnida, with 

 four orders ; 2, Insects, with eleven orders ; 3, Crustacea, with eleven orders ; 

 4, Epizoa, with three orders ; 5, Anellata, with four orders ; 6 Cirripedia, 

 with three orders. 



The Mollusca he divides into six classes : 1, Cephalopoda, with two orders ; 

 2, Gasteropoda, with ten orders ; 3, Pteropoda, with two orders ; 4, Lamelli- 

 branchiata, with two orders j 5, Brachiopoda ; 6, Tunicata, with two orders. 



