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Types of Crustacean Blood Coagulation. 



By 

 John Tait, M.D., D.Sc. 



{From the Marine Laboratory, Plymouth, and the Physiological Laboratory of Edinburgh 



University. ) 



Having been engaged at intervals during the last few years in studying 

 from a physiological point of view the coagulation of crustacean blood 

 — Tait (08), (10, A and B), (11) — and finding more variation in this 

 regard in different Crustacea than has hitherto been recognized, it 

 suggested itself to me to inquire if the observed differences are 

 correlated with any special physiological peculiarities, and, further, 

 if they depend in marked degree on phylogenetic relationship. It is 

 not a simple matter to settle either of these questions, and I make no 

 pretence to have done so. At the same time, I have thought it worth 

 while to put my observations on record, in the hope that the matter 

 may thus sooner arrive at a satisfactory settlement. 



The literature of the subject and details regarding the technique of 

 examination of the blood and other particulars I hope shortly to 

 publish elsewhere. Suffice it here to state that at least three distinct 

 modes of blood coagulation may be recognized in Crustacea : — 



A. Simple agglutination of the blood corpuscles without any 

 subsequent jellying of the blood plasma. (This is probably the 

 most primitive and essential device both in invertebrates and 

 vertebrates for procuring arrest of hsemorrhage from a wound.) 



B. Agglutination of the blood corpuscles with subsequent general 

 jellying of the plasma. 



C. Jellying of the plasma in two successive stages, the pre- 

 liminary cell -agglutination being relatively insignificant. The first 

 plasma coagulation consists of localized (primitively globular) 

 clots, which occur around or in immediate relation to special 

 blood corpuscles, originally discovered by Hardy (92), and by him 

 named " explosive corpuscles." At a later stage a second jellying 

 process occurs, which this time involves the whole of the remaining 

 plasma. 



