N. Stevens | Semantic Scholar

The effect of ultra-violet light upon the developing eggs of ascaris megalocephala

N. Stevens
Biology
Archiv für Entwicklungsmechanik der Organismen
1 June 1909

Summary1)When the development of one or more blastomeres of the eggs ofAscaris megalocephala in 2- or 4-cell stages, is prevented by exposure to the rays of ultra-violet light for 6 to 8 hours, the…

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Notes on regeneration in planaria lugubris

N. Stevens
Biology
Archiv für Entwicklungsmechanik der Organismen
1 December 1901

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A histological study of regeneration in planaria simplicissima, planaria maculata and planaria morgani

N. Stevens
Biology
Archiv für Entwicklungsmechanik der Organismen
1 August 1907

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Notes on regeneration in stentor coeruleus

N. Stevens
Biology
Archiv für Entwicklungsmechanik der Organismen
21 May 1903

In physiological regeneration and in regeneration after merotomy, the number of stripes in the frontal field is increased by intercalation of new light stripes, beginning several hours after the field has assumed its normal position.

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Notes on regeneration in Planaria simplicissima and Planaria morgani

N. Stevens
Biology
Archiv für Entwicklungsmechanik der Organismen
1 June 1909

P. morgani can be made to produce heteromorphic heads more readily than other Planarians that have been used for regeneration experiments and is especially favorable material for the artificial production of double-headed and double-tailed individuals.

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An unpaired heterochromosome in the aphids

N. Stevens
Biology
Archiv für Entwicklungsmechanik der Organismen
2005

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Regeneration in Polychoerus caudatus.

N. Stevens, A. Boring
Biology

Regeneration in Antennularia ramosa

N. Stevens
Biology
Archiv für Entwicklungsmechanik der Organismen
1 November 1902

Regeneration in A. ramosa appears, at least in early stages, to be adaptation of the already formed coenosarc to new conditions and needs, rather than to involve the building of new parts by cell multiplication.

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Experimental studies on eggs of Echinus microtuberculatus

N. Stevens
Biology
Archiv für Entwicklungsmechanik der Organismen
1 November 1902

Conclusions1)A part of an Echinus egg, containing a centrosome and a small number of chromosomes (4–12), may go as far as the fifth or sixth division after the operation, without returning to the…

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Regeneration in tubularia mesembryanthemum

N. Stevens
Biology
Archiv für Entwicklungsmechanik der Organismen
1 December 1901

Conclusions1)There is no quantitative relation between the number of red pigment granules in the circulating fluid of regenerating pieces of Tubularia, and the amount of red pigment in the new…

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