Proceedings of the American Philosophical Society Held at Philadelphia for Promoting Useful Knowledge, Томи 41 – 42The Society, 1902 |
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Сторінка 41
... cause of their great abundance in past geological periods , their relationships to other groups of animals are still so obscure as to make them objects of great interest to the general morphologist . At different times and by different ...
... cause of their great abundance in past geological periods , their relationships to other groups of animals are still so obscure as to make them objects of great interest to the general morphologist . At different times and by different ...
Сторінка 80
... causes them to crowd in toward the axis of the follicle . From a comparison of the extent of these growth regions in ... caused by the contraction of the muscle layer of the folli- cle , perhaps assisted by the pressure of the growing ...
... causes them to crowd in toward the axis of the follicle . From a comparison of the extent of these growth regions in ... caused by the contraction of the muscle layer of the folli- cle , perhaps assisted by the pressure of the growing ...
Сторінка 91
... causes them readily to adhere to needles or forceps . The mature colony has the appear- ance shown in Figs . 85 , 86 and 87. I have not heen able to isolate a single colony entire , for in teasing the long fibres are almost invariably ...
... causes them readily to adhere to needles or forceps . The mature colony has the appear- ance shown in Figs . 85 , 86 and 87. I have not heen able to isolate a single colony entire , for in teasing the long fibres are almost invariably ...
Сторінка 97
... caused by the confluence of the protoplasmic mass with one of the large cells on the margin of the testicle . Cirrepedia . 1886. Gilson figures the spermatozoa of Lepas anatifera and Balanas perforatus . They are flagellate , the ...
... caused by the confluence of the protoplasmic mass with one of the large cells on the margin of the testicle . Cirrepedia . 1886. Gilson figures the spermatozoa of Lepas anatifera and Balanas perforatus . They are flagellate , the ...
Сторінка 98
... caused by a fibre running spirally the length of the spermatozoon . The mature spermatozoon has the spirally twisted structure of a rope of tow . It contains a twisted central fibre , not visible externally , and the entire structure is ...
... caused by a fibre running spirally the length of the spermatozoon . The mature spermatozoon has the spirally twisted structure of a rope of tow . It contains a twisted central fibre , not visible externally , and the entire structure is ...
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Africa AMER AMERICAN PHILOSOPHICAL SOCIETY animals appear April Asia Australia auta autic beds belong blastopore body brachiopods Cambaroides Cambarus canals cells Central chromosomes cœlom connection contains crude oil Crustacea crystals curves Decapods deposits distillates distribution division domeykite drones eggs enteron Eocene equation evidence existence fact fauna Feb'y fertilization follicle formation forms fossils freshwater genera genus geographer geological Greater Antilles hydrocarbons islands Jan'y Jurassic land larva larvæ later Lower Cretaceous male mantle mass Mesozoic method Mexico Miocene nature Noctua North northern nuclei observed Ocean Oligocene origin parthenogenesis Pennsylvania petroleum Philadelphia PHILOS plate Pliocene polar body posterior Potamobius present probably PROC produced Prof queen region relation represented river sandstones separated shown solution South America southern species spermatocyte spermatogonia spermatozoa stage Terebratulina Tertiary theory tion Upper Cretaceous Zool