120 The Mastigophora 



a siliceous skeleton (Fig. 4. 9). The simplest type of secreted covering is 

 represented by the layer of "mucus" in Monas (Fig. 4. 3, E, F). Secreted 

 membranes may be thin, or they may be quite thick as in some of the 

 Coccolithina (Fig. 4. 2, K). Siliceous scales (Fig. 4. 2, G) or calcareous 

 coccoliths (Fig. 4, 10) are added to the membrane in various genera. In 



Fig. 4. 2. A. Dmobryon utriculus Stein, single loricate flagellate; x700 

 (after Pascher). B. Hyalobryon voigtii Lemmermann, a single flagellate 

 (colony shown in Fig. 1. 2, C); xlSOO (after Pascher). C. Cfnysococcus umbo- 

 natus with test; xl845 (after Conrad). D. Pseudokephyrion mmutissimum 

 Conrad, test only; x3000 (after C). E. Dinobryon stokesii Lemmermann, 

 single lorlca; x960 (after Pascher). F. Single lorica of Hyalobiyon lauterbornii 

 Lemmermann; x810 (after Pascher). G. Mallomonas dentata Conrad, chroma- 

 tophore, covering of siliceous scales (some bearing spines); x2500 (after C). 

 H. Stokesiella lepteca (Stokes) Lemmermann; xl045 (after S.). L Kephyrion 

 spirale (Lackey) Conrad, test only; x4500 (after C). J. Derepyxis amphora 

 Stokes; x880 (after S.). K. Syracosphaera mediterranea Lohmann, shell mem- 

 brane after dissolution of coccoliths in acid; single chromatophore; basal por- 

 tions of the two equal flagella; x2100 (after L.). 



