8 davenport academy of sciences. 



Genera of Chalarathoracida. 



Raphidiophrys Archer. 

 ' ^Acanthocystis Carter. * 



With two kinds of rays : siHcious raj's with branched ends 

 and dehcate pointed rays as in ActinopJirys. 



Genera of Desmothoracida. 



Clathrulina Cienk. 



Note. — Species of genera marked with the asterisk (*) in the above table of classifi- 

 cation have not, so far, been observed in this state. 



Class, SARCODINA. 

 Sub-class, RHIZOPGDA. 

 Order, AMCEBIDA. 

 Family, AMCEBID.^. 



AMCEBA Ehrenberg. 



With homogenous ectoplasm and more granular endoplasm. 

 Pseudopodia lobose, finger-like or pointed. Endoplasm enclosing 

 nucleus, contractile vesicles and inclusions. 



Amceba PROTEUS Leidy. 



Body of large size. Pseudopodia finger-like, or lobose. (Fig. 

 I, PL I.) 



Anixba prote7ts, the first Rhizopod in point of time to come un- 

 der the observation of the microscopist, is one of the most common 

 and widely distributed. 



In 1775 Rosel described this species, but it was the science of 

 more recent times that demonstrated the minute particle of proto- 

 plasm to have the essential characters of a single living cell and 

 to be the physiological source of specialized functions. 



Various characteristics render Amoeba protcus a most desirable 

 subject for biological studies: it is the largest and most common 

 species of the genus and can easily be obtained, at least in lim- 

 ited quantities ; the differentiation between ectoplasm and endo- 

 plasm is usually well marked, the normal activity of the organism 

 permitting the formation of pseudopodia to be readily observed. 



