78 



AQUATIC MICROSCOPY FOR BEGINNERS. 



Fig- 33- — Micrasterias rotata. 



Fig. 34. — Micrasterias truncdta. 



. Eiach semi-cell divid- 

 ed by two incisions 

 into one end-lobe 

 and two side-lobes, 

 each side-lobe by a 



shorter Cut divided into two parts, and each part 

 with two teeth. End-lobes broad, often with two 

 teeth on each end. M. trun- 

 cdta. Fig. 34. 

 b. Each semi-cell divided by deep 

 rounded depressions into four 

 tapering, slightly curved arms, 

 the whole desmid having eight 

 undivided arms. M. arcudta, 

 Fig- 35- 



Fig. 35. — Micrasterias 

 arcudta. 



Fig. 36. — Micrasterias 

 dich^toma. 



Fig. 37. — Micrasterias 

 Kitcheilii. 



