TMfe MicRosooPS;. 43 



ildmirable net-work and the refringent granules of the enchylema, 

 or that soft and plastic substance filling the meshes of the net- 

 Work, he then turns his attention to the central mass of proto- 

 plasm, where he discovers the nucleus containing shining, ir- 

 regular and fragmental bodies. Next he explores those darker 

 looking masses, of an irregular outline, and soon he discovers 

 that some contain embedded cells of Algte and others hide the 

 curiously sculptured carapace of some Diatoms. No doubt, 

 these are not parts of the animal nor are they formed by the 

 protoplasm-like inclavata, but must have been introduced from 

 the surrounding water, and such foreign bodies introduced into 

 the cells, we call inclusions. 



After this, the student directs his attention to the limiting 

 membrane of the cell and seeks to make out its structure and 

 to trace its relation to the net-work or the reticulum. Finally 

 he examines the mouth and the tentacle or flagellum. He is 

 not a little astonished to find in the latter ^ansverse striee simi- 

 lar to those of muscular fibies in the higher animals, and he 

 notices also its relation with the central protoplasm bv wavy 

 fibres of the reticulum. All this while the student has been 

 studying the anatomy of the jyovtiluai. But this is not all. 

 Whilst pursuing his observations thus far, the student could not 

 help seeing that the NoctUiwa moves ; and the anatomy of the 

 creature enables him now to begin the study of its movements. 

 First, he observes the most apparent movement, that by which 

 it progresses from place to place, and then he investigates the man- 

 ner in which this is effected, studying at the same time the mech- 

 anisnij the laws and the causes which control this movement 

 Of course he finds the chief cause in the flagellum, but possibly 

 he will suspect that this organ nnght be used also for the pre- 

 hension of food ? What a rich field for observation ! But these 

 observations would not be complete, were he not to direct his at- 

 tention to the interior movements of the protoplasm. What 

 life ! What activity! Here and there he sees the threads of reticu- 

 lum disappear and reconstruct themselves anew in a different di- 

 rection, shooting out new threads like pseudopodia. He has 

 seen the close relation of the reticulum with the interior striate 

 substance of the flagellum, and he suspects that the motor tissue 

 of all animals might be explained by considering the cells that 

 ■compose it as chiefly made up of the net-work of protoplasm. 



