ON ANIMAL LIFE. 575 



Birds are divided, according to the form of their bills, into six orders : 

 accipitres, as eagles, vultures, and hawks; picae, as crows, jackdaws, 

 humming birds, and parrots ; anseres, as ducks, swans, and gulls ; grallae, 

 as herons, woodcocks, and ostriches ; gallinae, as peacocks, pheasants, 

 turkies, and common fowls ; and, lastly, passeres, comprehending sparrows, 

 larks, swallows, thrushes, and doves. 



The amphibia are in some respects very nearly allied to birds : but their 

 blood is little warmer than the surrounding medium. Their respiration is 

 not necessarily performed in a continual succession of alternations, since 

 the whole of their blood does not pass through the lungs, and the circula- 

 tion may continue without interruption in other parts, although it may be 

 impeded in these organs, for want of the motion of respiration. They are 

 very tenacious of life ; it has been asserted on good authority that some of 

 them have lived many years without food, inclosed in hollow trees, and 

 even in the middle of stones ; and they often retain vestiges of life some 

 days after the loss of their hearts. Their eggs are generally covered with a 

 membrane only. They have sometimes an intermediate stage of existence, 

 in which all their parts are not yet developed, as we observe in the tadpole ; 

 and in this respect they resemble the class of insects. They are now uni- 

 versally considered as divided into two orders only ; reptilia, as the tortoise, 

 the dragon, or flying lizard, the frog and the toad ; all these have four feet ; 

 but the animals which belong to the order serpentes are without feet. 

 Most of the serpentes are perfectly innocent, but others have fangs, by 

 which they instil a poisonous fluid into the wounds that they make. In 

 England the viper is the only venomous serpent ; it is known by its dark 

 brown colour, and by a stripe of whitish spots running along its back ; but 

 to mankind its bite is seldom, if ever, fatal. 



The first three classes of animals have lungs, as we have already seen, 

 for respiration, and receive air by the mouth ; those which have gills, and 

 red blood, are fishes, residing either in fresh or in salt water, or indif- 

 ferently in both ; their eggs are involved in a membrane, and have no 

 albumen. Of the six orders of fishes, four have regular gills, supported 

 by little bones ; and they are distinguished, according to the place of their 

 ventral fins, into apodes, as the eel and lamprey; jugulares, as the cod; 

 thoracici, as the sole and perch, and abdominales, as the salmon and pike ; 

 distinctions which appear to be perfectly artificial, although useful in a 

 systematic arrangement. The two remaining orders are without bones in 

 the gills, those of the one being soft, and of the other cartilaginous or 

 gristly. These are the branchiostegi and chondropterygii of Artedi, which 

 Linne, from a mistake, classed among the amphibia. The sun fish, the 

 lump fish, the fishing frog, and the sea horse, are of the former, and the 

 sturgeon, the skate, and the shark, of the latter order. 



Insects derive their name from being almost always divided into a head, 

 thorax, and abdomen, with very slender intervening portions : although 

 these divisions do not exist in all insects. They are usually oviparous : 

 they respire, but not by the mouth ; they have a number of little orifices 

 on each side of the abdomen, by which the air is received into their rami- 

 fied tracheae ; and if these are stopped with oil, they are suffocated. In- 



