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Reproduction in <i>Littorina saxatilis rudissima</i> (Bean) and two other subspecies of <i>Littorina saxatilis</i> (olivi) at cullercoats, England

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Title Reproduction in Littorina saxatilis rudissima (Bean) and two other subspecies of Littorina saxatilis (olivi) at cullercoats, England
 
Creator Seshappa, G.
 
Description 222-229
Certain egg masses, collected on intertidal rocksurfaces at high tide levels at Cullercoats, were studied in detail and their identity established as those of the subspecies rudissima (Bean) of L. saxatilisi (Olivi). Early segmentation of the eggs was studied in freshly laid spawn from the field by rearing them in the laboratory; in addition, the animals were reared in the aquarium and spawning was observed. The 1st and 2nd cleavages of the fertilized eggs were vertical and resulted in 4 equal segments; the 3rd cleavage was horizontal. resulting in 4 larger lower macromeres and 4 smaller upper micromeres. The 4th cleavage, a vertical division, affected only the micromeres, resulting in 8 micromeres of equal size arranged in 2 alternating sets of 4 each over the set of 4 macromeres. Details of the cleavage could not be followed beyond the 12-celled stage and the embryos were beyond the 32-cell stage about a day after the collection of fresh spawn. Some systematic aspects are discussed and justification is given for treating the form rudissima (Bean) as a subspecies distinct from rudis and other forms. The three subspecies recognized are : L. saxatilis rudissima (Bean), L. saxatilis rudis (Maton) and L. saxatilis saxatilis (Johnston). The subspecies rudissima (Bean) is largely oviparous but shows the viviparous mode of reproduction in a small percentage of females at Cullercoats. The subspecies rudis (Maton) and saxatilis (Johnston) are always viviparous.
 
Date 2017-01-02T09:22:11Z
2017-01-02T09:22:11Z
1976-11
 
Type Article
 
Identifier 0975-1033 (Online); 0379-5136 (Print)
http://nopr.niscair.res.in/handle/123456789/39494
 
Language en_US
 
Rights CC Attribution-Noncommercial-No Derivative Works 2.5 India
 
Publisher NISCAIR-CSIR, India
 
Source IJMS Vol.05(2) [December 1976]