COMPARATIVE ANATOMY. 
VII. Strufhiones, struthious birds. Tlie 
largest of tlie class : possess extremely small 
wings, and are therefore incapable of flight ; 
biit riui very swiftly. 
J. Struthio, ostrich. 
g. Casuarius, cassowary or emu. 
(b) aquatic birds. 
Order I. 'Gralla, waders, frequenting 
marshes and streams ; long naked legs ; 
long neck ; cylindrical bill of diftereut 
lengths. 
1 . Ardea, crane, stork, heron, bit- 
tern. 
g. Scolopax, woodcock, snipe, cur- 
lew. 
3. Tringa, lapwing, ruffs, and reeves. 
4. Charadrius, plover. 
b. Fulica, coot. 
6. Rallus, rail. 
7. Phcenicoptenis, flamingo. 
8. Tantalus, .ibis, &c. 
II. Anseres, swimming birds ; web-foot- 
cd ; bill, broad and flat, covered by a some- 
what soft substance, on which large nerves 
are distributed. 
1. Colymbus, diver. 
g. Larus, gull. 
3. Procellaria, petrel. 
4. Diomedea, albatross. 
5. Pelecanus, pelican, cormorant. 
6. Anas, swan, duck, goose. 
7. Mergus, goosander. 
8. Alca, auk, puffin. 
9. Aptenodytes, penguin. 
The two 'Classes of cold-blooded verte- 
bral animals are the Amphibia and Fishes. 
The former, differing considerably from 
each other, have very few common charac- 
ters ; for in different instances they walk, 
fly, swim, and crawl. There is no external 
car, nor cochlea ; the brain is always very 
small ; the lungs are in the same cavity with 
the other viscera, and have very large air- 
cells ; no epiglottis, omentum, not mesen- 
teric glands ; two ovaries and oviducts ; 
cloaca, through which the faeces and urine 
are expelled, and in whieh the organs of 
generation terminate; neither hair, fea- 
thers, nor mammae ; skin either naked, or 
covered with scales ; both jaws are move- 
able ; there is an urinary bladder. 
Order I. Reptilia, having four feet, f qm-r 
drupeda ovipara.) 
1. Testudo, tortoise, turtle, 
g. Kana, frog, toad. 
3. Lacerta, lizards, crocodile, cha- 
meleon, newt, salamander, igu- 
ana, &c. 
II. Serpcntia. No external members; 
body of an elongated form, and viscera of a 
similar shape ; they are oviparous; but the 
egg is sometimes hatched in the oviduct; 
both Jaws moveable. 
1. Crotalus, rattlesnake. 
g. Boa. Immense serpents of In- 
dia and Africa. 
3. Coluber, viper. 
4. Anguis, blindworm. 
5. Amphisbaena. 
6. Caecilia. 
Fishes. Breathe by means of branchi® or 
gills ; and have no trachea, nor larynx ; or- 
gans of motion consisting of fins ; nose un- 
connected with the organs of respiration ; 
ear entirely inclosed in the head, the tym- 
panum, &c. being absent ; both jaws move- 
able; the place of the pancreas supplied by 
the pyloric c®ca ; an urinary bladder ; two 
ovaries ; heart consisting of a single auricle 
and ventricle. They may be distributed 
into two leading divisions : the cartilagi 
nous, whose skeleton consists of cartilage ; 
the bony, where it is formed of a more firm 
substance. 
(a) cartilaginous fishes. 
Order I. Chondropterygii ; having no gill- 
cover ; an uterus, with two oviducts. 
1. Petromyzon, lamprey. 
g. Gastrobranchus. 
3. Raia, skate, torpedo, stingray. 
4. Squalus, shark, saw-fish. 
5. Lophius, sea-devil, frog-fish. 
6. Balistes, file-fish. 
7. Chimmra. 
II. Branchiostegi ; having a gill-cover. 
1. Accipenser, sturgeon, beluga. 
g. Ostracion, trunk-fish. 
3. Tetrodon. 
4. Diodon, porcupine-fish. 
5. Cyclopterus, lumpsucker, 
6. Centriscus. 
7. Syngnathus, pipe-fish. 
8. Pegasus. 
(b) bony fishes, divided according Tft 
THE SITUATION OF THEIR FINS. 
Order I. Apodes; no ventral fins. 
1 . Mur®na, eel-kind. 
g. Gymnotus, electrical eel. 
3. Anarrhichas, sea-wolf, 
4. Xiphias, sw'ord-fisb. 
