EFFECTS OF TEMPERATURE ON THE MORPHOLOGY OF HEMOCYTES AND COAGULATION PROCESS IN THE MOLE-CRAB EMERITA (= HIPPA) ASIATICA

¹ Department of Zoology, University of Madras, Chepauk, Madras, Tamil Nadu, 600005, India

1. The hemocytes of Emerita asiatica have been studied in fresh preparations by phase contrast microscopy and also after staining.

2. With phase contrast microscopy, the following categories of hemocytes can be identified: (a) nondividing prohemocytes, (b) pleomorphic plasmatocytes, (c) intact and altering granular hemocytes, (d) quickly lysing cystocytes, (e) intact spherule cells, and (f) adipohemocytes.

3. This classification and terminology solve a long standing confusion in the nomenclature of hemocytes of decapods and enable comparisons between the different hemocyte types of crustaceans and the hemocyte types of other arthropods to be made.

4. Cystocytes and granular hemocytes constitute more than 95% of the hemocytes.

5. In thin wet films, the granular hemocytes undergo alterations which include loss of shape, refractility and granules, followed by vacuolization and disintegration leading to agglutination of the cells.

6. The alterations of the granular hemocytes are temperature-dependent, and lowering of the temperature results in progressive delay of the alterations.

7. There is no correlation between alteration of granular hemocytes and clotting time at different temperatures. At lower temperatures, gelification of plasma occurs when the granular hemocytes remain unaltered. The observations reveal that the granular hemocytes may not play any role in gelification of plasma. 8. Further, the process of cellular agglutination does not play any part in the phenomenon of plasma gelification, unlike this process in insects as reported by Grégoire.

9. Cystocytes, which have been referred to as explosive corpuscles by previous crustacean workers, disintegrate within a minute or two of exposure at all temperatures. Evidence supports their role in plasma gelification.

10. The observations also indicate that the substances liberated from the cystocytes initiate the stepwise transformation of granular hemocytes.