48 ESSAY ON CLASSIFICATION 



every class of organized beings contains some native natural group, 

 more or less extensive, more or less prominent, which is circum- 

 scribed within peculiar geographical limits. 



Among Mammalia we might quote further the Quadrumana, the 

 representatives of which, though greatly diversified in the Old as 

 well as in the New World, differ and agree respectively in many 

 important points of their structure; also the Edentata of South Amer- 

 ica. Among birds, the Humming Birds, which constitute a very nat- 

 ural, beautiful, and numerous family, all of which are nevertheless 

 confined to America only, as the Pheasants are to the Old World. ^"^ 

 Among Reptiles, the Crocodiles of the Old World compared to those 

 of America. Among Eishes, the family of Labyrinthici , which is con- 

 fined to the Indian and Pacific Oceans, that of Goniodonts, which is 

 limited to the fresh waters of South America, as that of Cestracionts 

 to the Pacific. The comparative anatomy of Insects is not sufficiently 

 far advanced to furnish striking examples of this kind. Among In- 

 sects, however, remarkable for their form, which are limited to par- 

 ticular regions, may be quoted the genus Mormolyce of Java, the 

 Pneumora of the Cape of Good Hope, the Belostoma of North Amer- 

 ica, the Fulgora of China, etc. The geographical distribution of 

 Crustacea has been treated in such a masterly manner by Dana, in 

 his great work upon the Crustacea of the United States Exploring 

 Expedition, Vol. XIII., p. 1451,^'^ that I can only refer to it for nu- 

 merous examples of localized types of this class, and also as a model 

 how to deal with such subjects. Among Worms, the genus Peripates 

 of Guiana deserves to be mentioned. Among Cephalopods, the Nau- 

 tilus in Amboyna. Among Gasteropods, the genus lo in the western 

 waters of the United States. Among Acephala, the Trigonia in New 

 Holland, certain Naiades in the United States, the Aetheria in the 

 Nile. Among Echinoderms, the Pentacrinus in the West Indies, the 

 Culcita in Zanzibar, the Amblypneustes in the Pacific, the Temno- 

 pleurus in the Indian Ocean, the Dendraster on the western coast 

 of North America. Among Acalephs, the Berenice of New Holland. 

 Among Polypi, the true Fungidce in the Indian and Pacific Oceans, 

 the Renilla in the Atlantic, etc. 



** What are called Pheasants in America do not even belong to the same family as 

 the eastern Pheasants. The American so-called Pheasants are generally Grouses. 



*' [James Dwight Dana, Crustacea, United States Exploring Expedition, Reports, 

 XIII, Philadelphia, 1852.] 



