AKCHERINA. 113 



apparently represents the nucleus. Occurring singly 

 and in tetraschistic colonies. The chlorophyl cor- 

 puscle, which takes the place of a true nucleus, is 

 unique, and sufficiently characteristic of this genus. 



1. Archerina Boltoni Ray Lankester. 



(Plate XIV, figs. 2-6.) 



Archerina Boltoni BAY LANKESTER in Q. J. Micr. Sci. XXV, 

 n.s. (1885), p. 61, t. vii, and in Encycl. Brit. ed. 9, XIX 

 (1885), p. 840, f. ii, 8-11. 



Body of each individual sphere about one-thousandth 

 of an inch in diameter, consisting of a sharply-defined 

 mass of refringent protoplasm from the surface of 

 which radiate stiff filaments, some of which are four 

 times as long as the diameter of the sphere and taper 

 from the base towards the extremity. The base of 

 each filament, according to Prof. Lankester (whose 

 description we quote), is relatively broad, and appears 

 to join, without penetrating, the surface of the sphere. 

 No membrane or pellicle can be detected on the surface. 

 Within the body is usually one large spherical vacuole ; 

 sometimes there are more, varying in size. 



Dimensions: Individual spheres, 1-2000" (Lankester}. 



Ponds near Birmingham, Mr. Thomas Bolton (after 

 whom the species was named), the generic name being 

 established in honour of Mr. William Archer. 



This rhizopod was found in great abundance in 

 pond-water, associated with desmids and other minute 

 chlorophyl-bearing alga3. Its spherical corpuscles 

 may at first, Professor Lankester says, be mistaken for 

 those of such microscopic plants, but a little attention 

 is sufficient to enable one to detect around many of 

 the bright green spheres a halo of radiant protoplasm 

 frequently in the form of very long and stiff filaments. 

 Once recognized it is not difficult to distinguish 

 Archerina, in its various phases of growth and multi- 

 plication, from its associates. 



8 



