ORDERS AMONG ANIMAES: ' 231 



instance, the Actinoids and Halcyonoids in the class of 

 Polypi, as circumscribed by Dana ; the Hydroids, the 

 Discophorse, and the CtenoMs among the Acalephs; the 

 Crinoids, Asterioids, Echinoids, and Holothurise among the 

 Echinoderms; the Bryozoa, Brachiopods, Tunicata, and 

 Lamellibranchiata among the Acephala; the Branchifera 

 and Pulmonata among the Gasteropods; the Ophidians, 

 the Saurians, and the Chelonians among the Eeptilcs ; the 

 Ichthyoids and the Anoura among the Amphibians, etc. 



Having shown, in the preceding section, that classes 

 rank next to branches, it would be proper to show 

 here that orders are natural groups, which stand above 

 families in their respective classes ; but for obvious rea- 

 sons I have deferred this discussion to the following 

 paragraph, which relates to families, as it will be easier 

 for me to show what is the respective relation of these 

 two kinds of groups after their special character has been 

 duly considered. 



From the preceding remarks respecting orders, it might 

 be inferred that I deny all gradation among all other 

 groups, or that I assume that orders constitute necessarily 

 one simple series in each class. Far from asserting any 

 such thing, I hold, on the contrary, that neither is neces- 

 sarily the case. But, to explain fully my views upon 

 this point, I must introduce here some other considera- 

 tions. It will be obvious, from what has already been 

 said (and the further illustration of this subject will only 

 go to show to what extent this is true), that there exists 

 an unquestionable subordination among the different 

 kinds of groups admitted in our systems, based upon the 

 different kinds of relationship observed among animals: 

 that branches are the most comprehensive divisions, in- 

 cluding each several classes, that, orders are subdivisions 



