QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by PARRY, G. Search for Related Content PubMed Articles by PARRY, G.

Journal of Experimental Biology 30,567-574 (1953)
Published by Company of Biologists 1953

Osmotic and Ionic Regulation in the Isopod Crustacean Ligia Oceanica

G. PARRY ¹

¹ Zoology Laboratory, University of Cambridge

1. Osmotic pressure of the blood of Ligia oceanica, measured by the freezing-point depression, has a mean value of 2.15 ± 0.04° C. (3.58% NaCl on weight/ volume basis).

2. Osmotic pressure of Ligia blood is much higher than that of other terrestrial isopods: Oniscus sp. 1.04° C.; Armadillidium sp. 1.18° C.;Porcellio sp. 1.30° C. or of the fresh-water Asellus sp. 0.50° C.

3. The osmotic pressure of the blood increases during the process of moulting, but no subsequent decrease is observed in the 4 days following.

4. Animals kept at low humidities lose water. They may be desiccated without permanent adverse effects until _blood is 3.48° C. ( 5.8% NaCl). Recovery to a normal level takes about 24 hr. in moist conditions.

5. In well-aerated sea water between 50 and 100% concentration, animals survive without much alteration in _blood. Above and below this range _blood rises and falls.

6. In animals kept on filter-paper moistened with distilled water _blood may fall to 1.44° C. (2.4% NaCl) without permanent adverse effects.

7. Analyses of inorganic ions in the blood show that sodium, potassium and chloride are all higher in concentration than in sea water; calcium is much more concentrated; and magnesium and sulphate much reduced.

Note:

Now at Bedford College, University of London.