258 PovsAH: A CRITICAL STUDY OF 
occurrence, on the surface of the medium around the edges of the 
culture, of a bright-colored line; this is pinkish to light orange 
yellow (Ridgway, 1912). Data on sixty-four numbers of Mucor 
show that thirty-four exhibited this color production, while twenty- 
eight numbers (Nos. 9, 10, 12, 24, 25, 26, 30, 34, 35, 38, 40, 41, 42, 
44, 46, 48, 49, 50, 51, 54, 58, 59, 61, 62, 63, 68, 73, and 2) formed 
no color at the top of the substratum. 
TABLE IV 
HEIGHT OF MUCORS ON BREAD, RICE, AND GRAPEFRUIT 
Species used Rice | Bread oa f Species used Rice | Bread by = 
Mucor No. 1.. 15 I5 I2 Mucor No. 36....| 30 Io 13 
Mucor No. 2.. 2 2 0.5| Mucor No. 37... 30 20 8 
Mucor No. 3.. 20 8 II ucor No. 38 20 10 17 
Mucor No. 4.. 20 30 I7 Mucor No. 39 30 I5 I5 
Mucor No. 5.. 25 I5 I9 Mucor No. 40 20 40 II 
Mucor No. 6.. 20 5 ro ucor No. 41 20 5 4 
Mucor No. 7.. 30 20 I2 Mucor No. 42 I5 2 
Mucor No. 9.. 35 8 13 Mucor No. 43 35 I2 It 
Mucor No. I0.. Io 25 I4 Mucor No. 44 3 3 
Mucor No. 11.. 13 Io 13. | Mucor No. 45 30 13 12 
Mucor No, 12.. 20 6 10. | Mucor No. 46 25 I2 II 
Mucor No. 13.. Io a Io Mucor No. 47 5 4 
Mucor No. 14.. 30 20 13 Mucor No. 48 -— 4 3 
coy No. 15.. Is q 8 Mucor No. 49 10 — 8 
Mucor No. 16.. 15 Io I5 Mucor No. 50 20 7 7 
ucory No. 18.. 30 I2 I5 Mucor No. 51 8 Io 5 
Mucor No. t9.. 35 Io Io | Mucor No. 54 S 3 Io 
Mucor No. 20.. 20 8 12 | Mucor No. 56 30 6 12 
Mucor No. 21.. 30 35 II Mucor No. 57 20 I2 II 
Mucor No. 22.. 35. + 10 13 No. 25 I5 12 
Mucor No. 23.. Io —_— 9 Mucor No. 59 Io 8 4 
Mucor No. 24.. 30 25 is Mucor No. 60 35 I2 I5 
Mucor No. 25.. 25 Io 7 Mucor No. 61 7 3 5 
ucor No. 26.. 50 40 aI Mucor No. 6 3 2 — 
ucor No. 28.. 25 25 18 Mucor No. 63 20 I5 Io 
Mucor No. 29.. 30 22 I2 Mucor No. 67 I5 — ge) 
Mucor No. 30. 15 9 I2 No. 68 20 20 20 
Mucor No. 31 20 20 13 Mucor No. 70 — ro I2 
Mucor No. 32 25 be 15 Mucor No. 72 Io Io 10 
Mucor No. 33 25 15 15 | Mucor No. 73 30 25 25 
Mucor No. 34 40 60 3 Mucor No. 74....| 15 3 10 
Mucor No. 35 25 12 19: | Mico Nos 96. sik 2s _ 17 
From the preceding experiments it has been shown that com- 
plex media are, on the whole, better for these plants than simple 
media, and as bread is a universally staple article easily obtained, 
as well as easy to work with, it has been used as a standard 
medium to grow these forms for taxonomic study. 
