Animal Life: A First Book of ZoölogyD. Appleton, 1900 - Всего страниц: 329 |
Результаты поиска по книге
Результаты 6 – 10 из 21
Стр. 69
... outer surface of the body is the food- taking organ . In the simplest many - celled animals , the sponges , there is no special food - taking and digestive organ . Each of the cells of the body takes in and assimilates food for itself ...
... outer surface of the body is the food- taking organ . In the simplest many - celled animals , the sponges , there is no special food - taking and digestive organ . Each of the cells of the body takes in and assimilates food for itself ...
Стр. 75
... outer surface of the body . But in these cases the food is ready for immediate absorption , so that no special treatment of it is necessary , hence no complex structures are required . Even were no such special treatment of the food ...
... outer surface of the body . But in these cases the food is ready for immediate absorption , so that no special treatment of it is necessary , hence no complex structures are required . Even were no such special treatment of the food ...
Стр. 76
... outer surface of the body . It is open to the outside of the body by two openings , and wholly closed ( except by its porosity ) to the true inside of the body . By the bending and coiling of the alimentary canal , and by the repeated ...
... outer surface of the body . It is open to the outside of the body by two openings , and wholly closed ( except by its porosity ) to the true inside of the body . By the bending and coiling of the alimentary canal , and by the repeated ...
Стр. 82
... outer circumferential wall of this hollow sphere ( Fig . 39 , ƒ ) . This is called the blastula or blastoderm stage of development , and the embryo itself is called the blastula or blastoderm . This stage also is common to all the many ...
... outer circumferential wall of this hollow sphere ( Fig . 39 , ƒ ) . This is called the blastula or blastoderm stage of development , and the embryo itself is called the blastula or blastoderm . This stage also is common to all the many ...
Стр. 91
... outer skin ( not the true skin , but a thin , firm covering or outer body wall com- posed of a substance called chitin , which is secreted by the cells of the true skin ) . In this second larval stage there can be seen the rudiments of ...
... outer skin ( not the true skin , but a thin , firm covering or outer body wall com- posed of a substance called chitin , which is secreted by the cells of the true skin ) . In this second larval stage there can be seen the rudiments of ...
Другие издания - Просмотреть все
Часто встречающиеся слова и выражения
adaptation adult alimentary canal Amaba ants become bees birds butterfly called cavity chitin CLASS colony color complex animals composed conjugation coral crab crustaceans degeneration differentiation digestion divide ectoderm egg cells existence eyes fauna feed female fish flagella free-swimming function gastrula Globigerinæ habits hatched higher animals host Hydra inclosed increase individuals insects instinct intestine islands jelly-fishes kinds of animals larva larvæ layer live male mals mammals many-celled animals mass medusa mouth opening naturalists nerve nest nucleus ocean one-celled outer oxygen Pandorina papillæ Paramecium parasites parent perform plants polyp prey primitive processes produced protective resemblance protoplasm Protozoa pseudopods pupa queen Radiolaria reflex action reproductive cells Sacculina sea-anemone shape shell simple simplest animals single cell special sense species sperm cells spherical spiders sponge stage structure substance surface swimming tentacles tion vertebrates Volvox Vorticella wings workers worms young
Популярные отрывки
Стр. 115 - There is no exception to the rule that every organic being naturally increases at so high a rate, that, if not destroyed, the earth would soon be covered by the progeny of a single pair. Even slow-breeding man has doubled in twenty-five years, and at this rate, in less than a thousand years, there would literally not be standing room for his progeny.
Стр. 215 - He cannot be mistaken for any other, and his flaming vest and blue stockings show that he does not court concealment. He is very abundant in the damp woods, and I was convinced he was uneatable so soon as I made his acquaintance and saw the happy sense of security with which he hopped about. I took a few specimens home with me, and tried my fowls and ducks with them ; but none would touch them. At last, by throwing down pieces of meat, for which there was a great competition amongst them, I managed...
Стр. 20 - ... inhabitants of the water has followed a roundabout path from the surface to the bottom and then back into the water. When this fact is seen in all its bearings and its full significance is grasped, it is certainly one of the most notable and instructive features of evolution. The food-supply of marine animals consists of a few species of microscopic organisms which are inexhaustible and the only source of food for all the inhabitants of the ocean.
Стр. 116 - The elephant is reckoned the slowest breeder of all known animals, and I have taken some pains to estimate its probable minimum rate of natural increase; it will be safest to assume that it begins breeding when thirty years old, and goes on breeding till ninety years old, bringing forth six young in the interval, and surviving till one hundred years old ; if this be so, after a period of from 740 to 750 years there would be nearly nineteen million elephants alive, descended from the first pair.