Dinobryacew 



47 



Genus Syncrypta Ehrenb., 1838. This is a motile colony 

 similar in appearance to Synura but invested with a mucilaginous 

 coat through which the cilia protrude. 



Syncrypta Volvox Ehrenb. is an abundant organism which bears great 

 resemblance to Synura Uvella. 



Genus Uroglena Ehrenb., 1838. In this colonial form the 

 cells are of the same nature as those of Synura, but the central 

 portion of the colony is a hollow space filled with mucilage, and 

 the ciliated cells are arranged round the periphery. 



Uroglena Volvox Ehrenb. is found in similar situations to those mentioned 

 for the two previous genera. It is, however, much less abundant. 



Family 3. DINOBRYACE^. 



The individuals are attached to the bottom of a cup-shaped 

 receptacle, which is widely 

 open above. They are con- 

 tractile and possess two cilia 

 of unequal length. 



Genus Dinobryon Ehr., 

 .1833. The cells are very 

 delicate, of a somewhat 

 changeable form, and are 

 sensitive to stimuli. The 

 lower end is attenuated into 

 a stalk which is attached 

 near the base of the open 

 receptacle. There is one 

 long cilium and one shorter 

 secondary cilium. The chro- 

 matophores are two in num- 

 ber and of a yellow -brown 

 colour. There is a pigment 

 spot, two contractile vacuoles, 

 and one cell-nucleus. The 

 receptacle is campanulate or 

 cylindrical, attenuated at its 

 lower end into a straight or 

 oblique point ; it is hyaline or sometimes coloured yellow or brown 



Fig. 7. A, Dinobryon cylindricum Imhof 

 var. dlvergens Lemm.; two living examples 

 from Eldwick, W. Yorks. ( x 730). B, en- 

 cysted condition of same. C, Dinobryon 

 Sertularia Ehrenb., colony with individuals 

 encysted, from Cornwall ( x 410) ; c, cysts. 



