ILLUSTRATIONS 



Plate 1 

 . An asexual coenobium of the typical form of Merrillospkat ra 

 africana. This is the youngest coenobium represented on the 

 plate. It measures 330 by 410 ti and contains one daughter 

 with two gonidia (nonsexual reproductive cells). The gonidia 

 are both about 30 n wide. Specimen 1. x 100. 

 . Another asexual coenobium of the same form. This is the most- 

 nearly mature coenobium on this plate. It measures 460 by 

 520 fi an4 contains two daughters, each with one gonidium and 

 one embryo. From left to right the third generation are: A 

 gonidium of 53 m; an 8-celled embryo of 54 m; a gonidium of 53 

 m; and a 2-celled embryo of 53 n. Specimen 2. x 100. 

 A somewhat younger coenobium of the same form. It measures 

 430 by 540 y. and contains two asexual daughters, each with 

 three gonidia. The four larger gonidia from left to right are 

 60, 57, 53, and 53 n, and the two smaller ones are 46 and 42 n. 

 Specimen 3. X 100. 

 A coenobium of the same form that is the next to youngest on the 

 plate. It measures 345 by 425 /* and contains two daughters, 

 each with four gonidia. The larger gonidia, from left to right, 

 are 38, 35, 38, and 40 M, and the smaller ones 22, 20, 22, and 

 100. 



i form, measuring 365 by 450 n, with two 

 r and three gonidia. In the left 

 i gonidium of 33 M width is mostly behind another 

 of the same size, and the two small gonidia are about 20 m 

 wide. In the right daughter the larger gonidia are about 30 m 

 and the small one is about 20 fi wide. Specimen 5. X 100. 

 Another coenobium of the same form, measuring 450 by 540 M, 

 and having three daughters. The gonidia in the left daughter 

 are about 50, 50, 30, and 30 m; in the right daughter 48, 40, 32, 

 and 32 n; and in the hindmost 32, 30, and 18 v.. Specimen 6. 

 X 100. 



Plate 2 

 An asexual coenobium of the same form of Merrillosphaera afri- 

 cana as all of those on the preceding plate. It measures about 

 450 by 550 /*, but bulges greatly on account of pressure of the 

 cover glass. It contains three offspring, one bisexual at the 



