Turbo, Haliotis, and Bapana. It is interesting to 

 note that Area, which belongs to the phj^logenet- 

 ically low order of Protobranchia, reacted very 

 strongly not only with Meretrix and Ostrea, but 

 also with the gastropods Turbo, Haliotis, and 

 Rapana. 



Wilhelmi (1944) applied the precipitation reac- 

 tion to the problem of determining the relationship 

 of the mollusca to other invertebrates. Using a 

 technique similar to that employed by Makino, 

 he made tests between two species of Busycon, 

 Pecten irradians, Nereis, Limjil.us, and Asterias 

 forbesi and concluded that, serologically, mollusca 

 are more closely related to annelids than to any 

 other group. At present this work has historical 

 interest only, since it is obvious that no broad 

 speculations about the relationship of various 

 phyla should be made on the basis of a few tests 

 made with only six species belonging to four 

 different phyla. 



The existence of serological differences in five 

 bivalves {Anadara inilata, A. larelu, Pecten yes- 

 soensi^, Ostrea (Crassostrea) yessoe/tsis, and 0. 

 circumpicta) was demonstrated by Tomita and 

 Koizumi (1951). In this work the serum was ob- 

 tained by centrifuging the blood withdrawn from 

 the auricles of the moUusk. Antisera were ob- 

 tained by injecting rabbits with increased doses, 

 starting with 1 ml. and adding 1 ml. each time 

 until 5 ml. were given on the 5th day. Blood was 

 taken on the 9th day after the last injection. In 

 homologous precipitation tests with C. gigas, i.e. 

 using the antiserum against the antigen of the 

 same species, positive reaction occurred in 1:16 

 dilution of antiserum with 1:12S0 dilution of 

 antigen. 



Finer differences between closely related species 

 were detected by absorption tests. When a cross 

 reaction is obtained in a test of an antiserum of 

 one species against the serum of a related organism, 

 it is assumed that the second organism possesses a 

 chemical substance connnon with the homologous 

 substances of the first one. If after the absorption 

 the serum still reacts with homologous sub- 

 stance, it is considered that the antiserum con- 

 tained antibodies to two or more chemical com- 

 ponents including the one which is common to 

 both. Using this method Tomita and Koizumi 

 found that absorption with C. gigas antigen re- 

 moved from C. circumpicta serum all antibodies 

 for gigas but not for circvmpicta. In another test 

 circumpicta removed from gigas antiserum all anti- 



bodies for circumpicta but not for gigas. The 

 authors' interpretation is that tliere are some com- 

 mon antigens between C. gigas and C. circumpicta 

 but that each also has its own specific antigen. 

 The investigators also found that Anadara {Area) 

 has all the antigens possessed by C. gigas plus its 

 owTi specific antigen. This is in accord with the 

 generally accepted view that Anadara (Area) is a 

 phylogenetically primitive form. Fresh-water 

 Anodonta showed no affinities with any other 

 species tested in this work. 



The application of absorption technique enabled 

 Numachi (1962) to show that the four local races 

 of C. gigas — Hokkaido, Miyagi, Hiroshima, and 

 Kumamoto — have some antigenic differences that 

 are in accord with their geographic isolation. 



Application of serological tests is a very promis- 

 ing method for studies of racial differences among 

 oysters. At present it is not known whether the 

 observed antigenic differences are hereditary 

 characteristics or are caused by differences in local 

 environment and particularly in the diet of oysters 

 from different localities. 



BIBLIOGRAPHY 



Bang, Frederik B. 



1961. Reaction to injury in the oyster {Crassostrea 

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 Barbour, Henry G., and William F. Hamilton. 



1926. The falling drop method for determining 

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 Barnes, T. Cunliffe. 



1937. Textbook of general physiology. P. Blak- 

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BfeLEHRXoEK, J. 



1930. Temperature coefficients in biology. Bio- 

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1935. Temperature and living matter. Protoplasma- 

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 Berthe, Jeanne, and Camille PETiTFRfeRE. 



1934a. L'automatisme cardiaque chez V Anodonte. 

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1934b. L'automatisme cardiaque chez V Anodnnle. 

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 Breder, C. M., Jr., and R. F. Nigrelli. 



1933. Lamellibranch leucocytes as living material 

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