5 66 



Phylum Chordata 



THE COMMONER ASCIDIANS OF AMERICAN COASTAL WATERS * 



PROCURING OF EGGS OR EMBRYOS 



For purposes of rearing, and developmental studies in general, 

 ascidians are to be divided into two groups according to whether they 

 are oviparous or viviparous (see above table). Except in a very few 

 instances oviparous ascidians are comparatively large and produce a 

 great many small eggs, viviparous ascidians are small and produce a 



* All these species are common shallow water forms; for further information con- 

 cerning distribution, habitat, and identification, see bibliography 3, 10, 11, 13-16. 



