124 



THE BIOLOGY OF MARINE ANIMALS 



TABLE 3.4 

 Cell Counts in Body Fluids 



(Data from Yeager and Tauber (140); Maluf (83); Kisch (73); Fange and Akesson (39). 



Methods of defence against haemorrhage come under the heading of 

 haemostasis, and show a progressive evolution in the animal kingdom. 

 The most primitive mechanism, found in all animals, consists of a con- 

 striction of the body wall or of the injured blood vessel, whereby the flow 

 of blood is reduced or stopped. Soft-bodied animals, such as polychaetes 

 and holothurians, constrict the body wall and contain their body fluids 

 until such time as the ruptured surface can regenerate. Animals with rigid 

 coverings, e.g. arthropods, must have recourse to other means. It is note- 

 worthy that even when a limb is autotomized in Crustacea, very little 

 blood is lost. In decapods practising autotomy a diaphragm extends across 



