Animal Studies: A Text-book of Elementary Zoology for Use in High Schools and CollegesD. Appleton, 1903 - 459 páginas |
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Página 25
... known as Infusoria , and , like the preceding spe- cies , are usually of microscopic size and of the most varied . shapes . The first striking feature of their organization is the presence of a delicate though relatively firm external ...
... known as Infusoria , and , like the preceding spe- cies , are usually of microscopic size and of the most varied . shapes . The first striking feature of their organization is the presence of a delicate though relatively firm external ...
Página 30
... known as tertian , quartan , and remittent . These malarial Hæmatozoa , .known generally as Hamamœba , can multiply by asexual sporulation in the blood , but produce also certain sexual individuals , which , when taken into the stomach ...
... known as tertian , quartan , and remittent . These malarial Hæmatozoa , .known generally as Hamamœba , can multiply by asexual sporulation in the blood , but produce also certain sexual individuals , which , when taken into the stomach ...
Página 32
... known that a workman is able to make better watch - springs , when this is his sole duty , than another who must make all parts of the watch ; and likewise , where a definite task is performed by a defi- nite structure , it is more ...
... known that a workman is able to make better watch - springs , when this is his sole duty , than another who must make all parts of the watch ; and likewise , where a definite task is performed by a defi- nite structure , it is more ...
Página 33
... known as Pandorina is represented , consisting of sixteen cells embedded in a spherical , jelly - like substance , each one of which is precisely like its companions in form and activity . The aggregation may be looked upon as a colo ...
... known as Pandorina is represented , consisting of sixteen cells embedded in a spherical , jelly - like substance , each one of which is precisely like its companions in form and activity . The aggregation may be looked upon as a colo ...
Página 34
... known as sperm - cells , de- velop a flagellum , and sep- arating from the colony swim actively in the sur- rounding water , where each finally unites with an egg . This union , like that of the two individuals in Vorticel- la ( Fig ...
... known as sperm - cells , de- velop a flagellum , and sep- arating from the colony swim actively in the sur- rounding water , where each finally unites with an egg . This union , like that of the two individuals in Vorticel- la ( Fig ...
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Palavras e frases frequentes
adapted adult alimentary canal amphibians animals annelids ants appearance appendages Arthropods attached bear become bees birds body burrow butterfly canal cavity cells chitin cilia clams colony color common consists crabs crayfishes crinoids Crustacea digestive dorsal earthworm eggs enemies esophagus exist external eyes feed feet female fins fishes flagellum flatworms forms fresh-water frogs gastrula gills habits hatched head highly host individuals insects instinct intestine jelly-fish kinds of animals known lancelet larva larvæ legs limbs live lizards male mals mammals mollusks mouth muscles natural nerve nest notochord organs oxygen pair parasites parent plants plates possess prey protection Protozoa queen relatively reptiles resemblance rocks Sacculina salamanders segments sense serve shell side skeleton skin snails snakes species spines sponge squirrel stage stomach structure substance surface surroundings swimming tail teeth tentacles tion usually various vertebrates wings workers worms young
Passagens conhecidas
Página 282 - 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.
Página 211 - Its summer plumage so exactly harmonizes with the lichen-coloured stones among which it delights to sit, that a person may walk through a flock of them without seeing a single bird; while in winter its white plumage is an almost equal protection.
Página 264 - Fig. 41 are indistinguishably alike, but one embryo is sure to develop into a fish and the other into a salamander. This certainty of an embryo to become an individual of a certain kind is called the law of heredity.
Página 343 - Tremex burrow is reached she deposits an egg in it. The larva that hatches from this egg creeps along this burrow until it reaches its victim, and then fastens itself to the horntail larva, which it destroys by sucking its blood. The larva of...
Página 362 - 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...
Página 329 - Steppes, he once saw an eagle belonging to an altogether gregarious species (the white-tailed eagle, jfaliaetos albicilla) rising high in the air ; for half an hour it was describing its wide circles in silence when at once its piercing voice was heard. Its cry was soon answered by another eagle which approached it, and was followed by a third, a fourth, and so on, till nine or ten eagles came together and soon disappeared.
Página 283 - 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.
Página 363 - There are two intensely black spots on this margin in the appropriate position for eyes, and the whole appearance is that of a large flat face extending to the outer edge of the red margin. The effect is an intensely exaggerated caricature of a vertebrate face, which is probably alarming to the vertebrate enemies of the caterpillar. . . . The effect is also greatly strengthened by two pink whips which are swiftly protruded from the prongs of the fork in which the body terminates. . . . The end of...