360 Antisera for Arfhrojwda 



positive results with the Decapoda and these were very slight. Good 

 reactions were however obtained with dilutions of spider sera. 



The results of these tests indicate a fairly close relationship between 

 the King-crabs and the Spiders, and a very distant one between the King- 

 crabs and the Decapoda. These sera were much more powerful than 

 the anti-egg, and anti-Chelonian sera which interacted, and it might 

 have been expected that even with distant relationship the sera of the 

 Decapoda would have produced at least small reactions. 



During its collection the anti-crab serum behaved in a rather curious 

 manner. The blood clotted rapidly, and a very milky serum separated 

 from the clot. The latter in a short time also coagulated, and from this 

 coagulum a clear serum eventually came off. 



Anti-Limulus I behaved in the same way, but only a very partial 

 coagulation of the serum first separated took place. 



In the previous tables the reactions produced with all specimens, 

 whether preserved in a fluid or dried condition, have been given. Some 

 of the latter, owing to overheating during the process of drying in the 

 sun, or some other cause, failed to go into solution and consequently the 

 tables of percentages of positive results are probably somewhat under- 

 estimated. The results of the actions of the antisera to the Avian egg- 

 albumins and Reptilian sera with the egg-albumins, and fluid Reptilian 

 sera are, therefore, given below. In the other groups very few fluid 

 sera were used, and their reactions with the various antisera may be 

 seen in the tables at the end. 



Percentage of well-marked positive reactions with Antisera to 



The present experiments can only be regarded as of a preliminary 

 nature, and indicate the interesting results which might be obtained by 

 systematically following up this line of research. For more accuratie 

 and trustworthy results both quantitative and qualitative tests would 

 have to be undertaken with fluid sera obtained from healthy animals 

 and repeated two or three times. Most of the experiments, which 

 are the subject of this paper, have only been done once. Had it been 



