RHODO-THIOBA CTERIA 



153 



Thioporphyra volutans (Ellis). 



Literature. — Ellis (9), 1926. 



Description. — Mass cultures are usually found as a purple 

 mantle covering seaweed decomposing in shallow pools. Under 

 the microscope the large purple cells, of an ovoid or spherical 

 form, which are in active movement, are striking objects. 

 In addition, the cells contain numerous sulphur inclusions. 



The organism is normally either a large unicoccus (Fig. 34a) 

 or a large diplococcus (Fig. 34^). Under certain conditions, 



Fig. 33. — Thioporphyra volutans (Ellis). 

 a. — Tricoccus in triangular formation. x 3000. 

 b. — A tricoccus in linear formation. This form of tricoccus is exceptional. 



X 3000. 

 c. — A diplococcus showing three of the structures which maj' be endospores. 



In the cell a single sulphur globule, with its characteristic thick, 



black, peripheral ring is shown, x 5000. 



connected with reproduction, tricocci may be formed (Fig. 33 

 a and b). The plasma may occupy only the peripheral portion 

 of the cell, leaving a large vacuole in the centre (Fig. 34^^) ; or 

 it may be reticulate (Fig. 34^^), or peripherally placed but with 

 uneven distribution, the bulk of it being concentrated at one 

 end if the cell is ovoid (Fig. 34c). The average thickness of the 

 cells is 7ju,. The purple colouring matter is diffused throughout 

 the plasma. The cytoplasm is slightly granular, and is 

 readily stained by iodine, methylene blue and similar reagents. 

 It is bounded on the outside by a readily distinguishable 



