1910.] Huxley's CJassificniiou oj 1872. 93 



VI. Edentate Series. 

 Order Bruta, or Edentata. 



Subclass Didelphia. 

 Order Marsupialia. 



Subclass Ornithodelphia. 

 Order Monotremata. 



HUXLEY, 1872. 



'A Manual of the Anatomy of Vertebrate Animals. 



In this classification de Blainville's three-fokl division of the Mammalia is 

 followed. Haeckel's division (1866) of the Monodelphia into two series, 

 in accordance with the deciduate or non-deciduate character of the placenta 

 is provisionally accepted as explained in a foot-note. The Hyracoidea had 

 been given separate ordinal rank in Huxley's 'Introduction to the Classifi- 

 cation of Animals' in 1869. 



Huxley s Classification, of 1872. 



I. — Ornithodelphia. 



1. Monotremata. 

 II. — Didelphia. 



2. Marsupialia. 

 III. — Monodelphia.' 



a. Median incisor teeth are never developed in either jaw. 



3. Edentata. 



b. Median incisor teeth are almost always developed in one or both jaws. 



i. The uterus develops no decidua (Non-deciduata). 



4. Ungulata. 



5. Toxodontia (?) 



6. Sirenia (?)=. 



7. Cetacea. 



ii. The uterus develops a decidua (Deciduata). 

 a. The placenta is zonary. 



8. Hyracoidea. 



9. Proboscidea. 

 10. Carnivora. 



/?. The placenta is discoidal. 



11. Rodentia. 



12. Insectivora. 



13. Cheiroptera. 



14. Primates. 



1 "The manner in which tlie Monodelphia are liere subdivided must be regarded as merely 

 provisional." 



2 "The placentation of the Toxodontia and Sirenia is unknown." 



