The Sarcodina 211 



Suborder 3. Desmothoracina. In this group, there is a non-siliceous 

 (108) one-piece test (Fig. 5. 2, B) containing pores through which pseu- 

 dopodia are extended. Certain genera contain sessile types with stalks. 

 The stalk in Hedriocystis (Fig. 5. 7, G, H) is said to be merely an exten- 

 sion of the body resembling a slender pseudopodium (144). In Clathru- 

 lina (Fig. 5. 8, E-H), the young organism first develops a protoplasmic 

 stalk by outgrowth from the body. An outer covering is then secreted 





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Hill 



Fig. 5. 8. Desmothoracina: A. Hedriocystis reticulata Penard, x500 ap- 

 prox. (after P.). B. Choanocystis lepidula Penard, x730 approx. (after P.). 

 C. Clathrella foreli Penard; diameter of test, 40-55/i (after P.). D. Elastcr 

 greefi Grimm, x700 (after Penard). E-H. Clathrulina e/ega?J5 ^ienkowski: ' 

 cytoplasm grows down over the original stalk (F) and produces a hollow 

 stalk (G), which becomes continuous with the test in older forms (H); 

 schematic (after Valkanov). 



