The American Naturalist, Volume 41Essex Institute, 1907 |
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Expressions et termes fréquents
adult Agric AMERICAN NATURALIST animals appear Aramides basal birds Blarina Botanical Bull burrows Catalogue characters cilium closely collection color cones Creek cycads described distribution dorsal eggs embryo evidence female fertilization figure fish flora forms fossil Fusus gastropods genera genus glands Holmesburg illustrated insects laboratory larva larvæ later leaf leaflets leaves length lobes male Moropus Museum Mutation Natural History Neshaminy Creek nest Notes nucleus observed occur pair paper parasites petiole PH.D Philadelphia Co plants Pleistocene pleopods Polyodon portion posterior present probably Proc Professor prothallial cells protoconch Rafinesque region River E. D. Cope segments setæ sexual ratio shells shown shrew side snails species specimens spermatophores spermatozoa spike spines spiracle spirals sporophyll spouting stage structure surface telson theory tion Tubinares U. S. Nat University vertebrates Volvox weever fishes whorls young Zool Zoology
Fréquemment cités
Page 654 - Given any species in any region, the nearest related species is not likely to be found in the same region nor in a remote region, but in a neighboring district separated from the first by a barrier of some sort, or at least by a belt of country, the breadth of which gives the effect of a barrier.
Page 26 - The valid name of a genus or species can be only that name under which it was first designated on the condition: (a) That (prior to January 1, 1931) this name was published and accompanied by an indication, or a definition, or a description; and (b) That the author has applied the principles of binary nomenclature.
Page 219 - ... parent. In theory, either of these conditions might exist. In fact, both of them are virtually unknown. In nature a closely related distinct species is not often quite side by side with the old. It is simply next to it, geographically or geologically speaking, and the degree of distinction almost always bears a relation to the importance or the permanence of the barrier separating the supposed new stock from the parent stock.
Page 373 - Secondly, there are two colors, namely, yellow and blue, which also if unalloyed we see, so far as can be ascertained, in the normal manner. But these two are the only colors of which we have any sensation.
Page 374 - But, when I examine more closely what I really do see, I am obliged to come to the conclusion that the sensation I perceive is not one that I can identify separately, but is simply a modification of one of my other sensations ; namely, yellow. It is, in fact, a yellow, shaded with black or gray, ' — a darkened yellow, or what I may call yellow brown.
Page 347 - On rising from the water the movements of the tail are continued until the whole body is out of the water. While the tail is in motion the...
Page 214 - ... this predominance varying from an absolute, or almost absolute completeness that approaches the commonly complete dominance of the sexual characters, to a blend intermediate between the crossed varieties. Thus in the case of poultry, " very frequently, if not always, the character that has once been crossed has been affected by its opposite with which it was mated and whose place it has taken in the hybrid. It may be extracted, therefrom, to use in a new combination, but it will be found altered....
Page 469 - ... the eggs by several layers of bigger stones, thereby preventing them from being washed away by the stream or being carried off by water-birds fond of this kind of caviare, or by marauding little fishes. The material for this defensive structure is derived from the above-mentioned ring, which thereby becomes devoid of all stones and gleams brightly in its smooth garb of white sand. It is wonderful to observe the accuracy of the fishes' handiwork and the perfect circle described by the ring.
Page 541 - PP 56 Geography and geology of a portion of southwestern Wyoming, with special reference to coal and oil, by AC Veatch. 1907. —pp., 26 pis.
Page 349 - Mus., zool. ser., 6:iv+76i. 1907. A catalogue of the collection of mammals in the Field Columbian Museum.