NOCTILUCA 



767 



lti ID. which vibrates freely ill its interior. The central proto- 

 plasmic mass sends ofl' in all directions branching prolongations of 

 its substance, whose ramifications inosculate ; these become thinner 

 and thinner as they approach the periphery, and their ultimate 

 filaments, coming into contact with the delicate membranous body 

 wall, extend themselves over its interior, forming a protoplasmic- 

 network of extreme tenuity (fig. 588). Besides these branching 

 prolongations, there is sent oft' from the central protoplasmic mass a 

 broad, thin, irregularly quadrangular extension (fig. 587, B. /*), which 

 extends to the superficial rod-like ridge, and seems to coalesce with 

 it: its lower free edge h.-is a thickened border; whilst its upper 

 edge becomes continuous with a plate-like striated structure, y. wliich 

 seems to be formed by a peculiar duplicature of the body-wall. At 

 one side of the protoplasmic mass is seen a spherical vesicle. J>. of 



PIG. 588. Portion of superficial protoplasmic reticulation formed 

 by ramification of an extension of central mass. (Magnified 

 1,000 diameters.) 



about T.-j'-g^ths of an inch in diameter, having clear colourless 

 contents, among which transparent oval corpuscles may usually be 

 detected. This, from the changes it undergoes in connection with 

 the reproductive process, must be regarded as a nude us. 



The particles of food drawn into the mouth (probably by the 

 vibrations of the flagellum) seem to be received into the protoplas- 

 mic mass at the bottom of the (esophagus by extensions of its sub- 

 stance, which inclose them in filmy envelopes that maintain them- 

 selves as distinct from the surrounding protoplasm, and thus consti- 

 tute extemporised digestive vesicles. These vesicles soon find their 

 way into the radiating extension* of the central mass (as shown in 

 fig. 587. B). and are ensheathed by the protoplasmic substance which 

 goes on to form the peripheral network (fig. 589). Their number 

 and position are alike variable ; sometimes only one or two are to 

 be distinguished : more commonly from four to eight can be seen; 



