Peridiniaceas 



71 



place of junction on the anterior schizont 'the attachment area,' and the 

 depression ' the chain channel ' (consult fig. 53). 



Lohmann observed heteromorphic chains of Ceratium tripos, and Kofoid 

 has given some interesting information on two cases of mutation, one of 

 Ceratium tripos to C. calif or niense, and the other of C. Ostenfeldii to 

 C. californiense. In the rare instances in which mutations occur, Kofoid 



Fig. 51. Peridinium anglicum G. S. West. A, ventral view; B, dorsal view; C, apical view; 

 D, antapical view; E, thin-walled 'cyst' within old wall; F, escaped 'cyst'; G and H, 

 division of escaped 'cyst'; f, escape of an elongated '-cyst' from old wall; /, escape of 

 naked motile individual from ' cyst ' ; A' and L, divisions of naked motile state. All x 500. 

 In fig. C: 1'- 3', apical plates; 1" 7", precingular plates; 1, anterior intercalary plate. 



finds very abrupt changes involving a whole complex of fundamental 

 characters, so that in one, or at most in two generations of asexually- 

 produced individuals the descendants differ profoundly from the ancestral 

 type. The 'fact that the mutating chains have been seen so rarely in 

 comparison with the vast numbers of normal chains which have been 



