JOURNAL OF MICROSCOPICAL SCIENCE. 



DESCRIPTION OF PLATE XVIII, 



Illustrating Professor AUmaii's paper on Noctiluca . 



Fig. 



1. — Noctiluca miliaris viewed from the ab-oral side, a. The entrance to 

 the atrium ; c, the superficial ridge ; d, the flagellum ; h, the 

 nucleus. 



In two of the radiating processes nutritive matter is seen enclosed 

 in extemporaneously formed cysts, and some oil-globules (?) are seen 

 adhering to the surface of the central protoplasm. Magnified about 

 100 diameters. 

 2. — The animal viewed in a plane at right angles to fig. 1. a, Eutrance to 

 atrium ; b., atrium ; c, superficial ridge ; d, flagellum ; e, mouth lead- 

 ing into gullet ; the oesophageal ridge, with its tooth-like process, is 

 seen projecting from the walls of the gullet into its cavity, and the 

 vibratile cilium is seen springing from its floor ; /, broad process 

 extending from the central protoplasm to the superficial ridge 

 g, duplicature of walls ; h, nucleus. 



Oil-globules (?) are seen adhering to the surface of the central 

 mass, and nutritive matter is seen in vacuoles formed extempo- 

 raneously in some of the radiating offsets, 



3. The animal viewed in a position intermediate between that of fig. ] and 



that of fig. 2. «, Entrance to atrium ; b, atrium ; c, superficial ridge ; 

 d, flagellum ; f, broad process extending from central protoplasm to 

 superficial ridge ; g, duplicature of walls. 



In the central protoplasm some diatoms are seen enclosed in a 

 vacuole, and another vacuole also enclosing nutritive matter is seen 

 in one of the protoplasm strings. 



4. The animal acted on by a solution of iodine. The protoplasmic con- 



tents have separated from the external structureless wall, a. Entrance 

 to the atrium. 



5. The nucleus isolated, a, Its ordinary appearance under the microscope ; 



b, its appearance when acted on by acetic acid. 



6. A portion of one of the branching offsets from the central pro- 



toplasm. 



7. Portion of the peripheral layer, showing cell-like bodies immersed in a 



finely granular protoplasm. 



8. The central protoplasm mass after the discharge of all the solid residue 



of digestion. 



