Notes on the Swimming Methods and Habits of Certain Crustacean Larvæ

The swimming methods and habits of certain Decapod larvse have been observed. The first larva ofMunida bamfficawas chosen for special attention. Such a study shows the importance of (1) orientation, (2) the presence of a reversal mechanism. Observations on other types show these factors to be of great importance and also show that there are a great variety of attitudes in which larvæ swim. Points in the relation of the larvæ to their environment were next considered; orientation is again important here, but whereas in Munida larvæ a “resting” orientation is found no such attitude is seen in Brachyurous zoeas.