Io6 yournal of Cojiiparatwe Neurology and Psychology. 



the surface, and a conical portion which projects from near the 

 middle of the flattened portion into the hyaline layer almost to the 

 surface of the colony. At a point about halfway between the 

 anterior pole and the equator of the colony, the altitude of the 

 projection is about twice as great as the diameter of its base. The 

 ratio between these dimensions becomes gradually greater as one 

 proceeds farther from the anterior end, until at the posterior end 

 the altitude is four to five times as great as the diameter. It will 

 thus be seen that the distal end of the conical projections gradually 

 extends farther out as one proceeds from the anterior end to the 

 posterior (see Fig. 2). The only reference to the variation in 



Fig. 3. View of the anterior end of a colony of Volvox minor, showing the location of the eye-spots. 

 Z, zooids; e, eye-spots; p, protoplasmic fibers connecting the zooids. 



form of zooids in the same colony is found in Overton's article 

 ('89, p. 70), and he states only that the projection (Schnabel) 

 is longer in the neighborhood of injured places ("In der Nahe 

 von verletzten Stellen verlanget sich der Schnabel"). 



The projection is nearly circular in outline at the base, but it 

 becomes considerably flattened toward the distal end, so that a 

 cross section near this end is elliptical in outline. The zooids 

 are so arranged in the colony that one of the flattened surfaces of 

 the projections faces the anterior end and the other the posterior. 

 Viewed from either of the flattened surfaces, the outline of the 

 distal end forms nearly a straight line, at either end of which is 

 found the attachment of a flagellum. The flagella are five or six 

 times as long as the diameter of the zooids. Overton ('89, p. 72) 



