INTRODUCTION. 13 
Orper 1. Myrrapopa. Pl. 74, fig. 37, Scolopendra. 
6 66 
¢ 9. THysANURA. : 38, Lepisma. 
 =63. Pamasrra. ef * 39, Pediculus. 
«© 4, Sucrorta. a “ 40, Pulex. 
«¢ 5. CoLEopTERA. + 41, Carabus. 
‘© 6. ORTHOPTERA. cS 42, Forficula. 
«7, HEMIPTERA. ye 43, Cimen. 
“¢ 8. N&EUROPTERA. 4 “ 44, Labellula. 
© = 9. Hymenoprera. “ “ 45, Tenthredo. 
‘10. LepmopTeERa. a “ 46, Vanessa. 
“ 11. Drerera. r “ 47, Stomocys. 
Division IV. VERTEBRATA. 
Tae Verresrate Drviston of the animal kingdom, as has been already 
remarked, includes animals with an internal articulated skeleton or 
framework, capable of growth, supplied with blood-vessels and nerves, and 
serving for the support of the soft parts; and it is here that animals of the 
greatest size are found. The body is divided into head, trunk, and organs 
ot locomotion, and the nervous system has attained its greatest concentration 
in a single brain or nervous centre. The group of Vertebrata having the 
same value as the previous Divisions, it is unnatural to consider it as 
balancing the Evertebrata conjointly, and on this account it will be here 
considered as a division including the following classes. 
Olass 1. Pisces. 
In all fishes the blood is oxygenated by means of gills, which are 
supported by a bony framework, named the branchial arches, which 
generally amount to four. The external structure is adapted for inhabiting 
and moving through the water. The air-bladder, although not concerned 
in breathing, is really the homologue of the lungs in the higher classes. It 
is not present in all fishes. 3 
Fishes are divided into two series, according as the skeleton is 
cartilaginous or osseous. In the former the organization is low, the ribs 
are rudimentary, and in the lowest form the spine is a continuous line of 
cartilage not yet divided into vertebree. The orders of cartilaginous or 
chondropterygeous fishes are as follows: 
Orvrer 1. Cyctosromara. Pl. 74, fig. 48, Petromyzon, lampereel. 
* . 2. SELACHIL. y “49, Squalus, shark. 
‘¢ 8. STURIONEs. . “ 51, Acipenser, sturgeon. 
The osseous fishes, which are much the most numerous, are distributed 
in the following orders : 
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