124 



CRYPTOPHYCEAE 



It is suggested that the group is still actively evolving, and that 

 some of the brown types with algal characters may have a relation- 

 ship with the simpler Phaeophyceae. 



CRYPTOPHYCEAE • 



Fig. 87 



Very little is known about this group. They are mostly specialized 

 flagellates with two fiagellae but there are a few algal forms, although 

 none of them is filamentous. The morphological types are : 



(a) Naked motile unicells. 



(b) Colourless unicells. 



Fig. 87. Cryptophyceae. A, Cryptomonas anomala, side view. B-D, Tetra- 

 gonidiuni verrucatum, D, being the swarmer. /= furrow, n = nucleus, p = pyrenoid, 

 5 = starch. (After Fritsch.) 



(c) Symbiotic unicells with cellulose walls, e.g. some of the 

 Zooxanthellae which are found associated with Coelenterata and 

 Porifera. 



{d) Palmelloid type, e.g. Phaeococcus, which is found on salt marsh 

 muds in England. 



(e) A single coccoid type, Tetragonidium. 



The number of chloroplasts varies, pyrenoids are present, and 

 there is one nucleus in each cell. Reproduction is by means of 

 longitudinal fission but some species also form thick-walled cysts. 



