XV, 6 
Shaw : Camp bellosphaera 
509 
gonidium. These embryos are all in the same stage. The same 
specimen is shown in fig. 16 on a smaller scale for comparison 
with fig. 17. 
The separation of the gonidia in the daughters is shown in 
Plate II, fig. 17, a mother coenobium (specimen 29) containing 
six daughters and one gonidium. In all of the daughters the 
gonidia have become separated, and they can be counted by fo- 
cusing the microscope. The number in each case is eight. In 
this stage the species is not easily distinguishable from Volvox 
carteri Stein. 
The variation and graduation in size of the gonidia in the 
same coenobium, and the consequent gradation in advancement 
of sister embryos, may be practically lacking, as shown by figs. 
15 and 17 of Plate II. On the other hand, a multitude of speci- 
mens can be found with a gradation as pronounced, and an 
arrangement as symmetrical, as is shown in Plate II, fig. 14, 
which shows an asexual specimen (No. 30), containing six 
gonidia arranged in three alternating pairs. This is from slide 
1 of the pond J material. 
The number of somatic cells estimated to occur in the speci- 
mens described, together with the number of reproductive cells 
counted in each case, are given in Table I. 
Table I —Number of cells in Campbellosphaera obversa. 
Asexual coenobia. 
Sexual coenobia. 
Specimen No. 
Somatic 
cells. 
Repro- 
ductive 
cells. 
Specimen No. 
Somatic 
cells. 
Repro- 
ductive 
cells. 
12 
3, 520 
6 ! 
21 
2, 960 
22 
1 
3,470 
7 
18 . 
2, 660 
17 
11 
3,080 
7 i 
19 
8, 460 
28 
25 
2, 850 
20_ 
2, 360 
29 
2,830 
17 
2, 330 
23 
10.. 
2, 675 
14 _ _ 
2,300 
28 
22 
2, 640 
7 
13 
2,200 
23 
2 
2, 635 
8 i 
16 
1.920 
23 
26 
2,670 
9 ■ 
3 
2, 520 
8 
4 
2,425 
6 1 
23 
2, 420 
6 
24 
1,400 
6 
2,370 
6 i 
23 a Daughter, . 
1,250 
16 
7 
2, 370 
6 ' 
5 
2,280 
6 I 
2, 190 
8 
645 
16 
168743 2 
