1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 215 
spores, which are with difficulty distinguished from the true zygo- 
spores. Superficial inspection under low magnifications would 
undoubtedly lead to their classification as zygospores, but it is not 
unlikely that in our records, especially the earlier ones on C. berthol- 
letiae, contrasts may have been listed as weak zygospore reactions, 
TABLE X 
SUMMARY OF REACTIONS es DIFFERENT SPECIES OF ee 
Z INDICATES ZYGOSPORES; SMALL LETTERS INDICATE GRADE 
IMPERFECT REACTIONS 
C. bertholletiae C. echinulata C. elegans 
217 plus 266 minus | 885 plus 886 minus | 406 plus | 506 minus 
ee ho ogg 
DNS ee fe O c O ¢c 
266 mings. Oe c O c O 
C. echinulata 
O58 WME oo. O Coc pee. | Z O oO 
$86 minus... .:.... c O fe eee ne oO O 
C. elegans 
AO0 Paes O c O OF eee, Z 
Writs: c O O O De 
TABLE XI 
Cunninghamella A: UNGRADED “IMPERFECT HYBRIDIZATION” REACTIONS WITH PLUS 
AND MINUS Mucor TESTERS H AND D; H IN BODY OF TABLE 
DICATES IMPERFECT REACTIONS 
Plus races Minus races 
Mucor 
515 | 242 | 759 | 260 | 273 | 522 | 182 | 269 | 188 | 95 | 370 | Sit | 245 
H plus howe rs Oro ro 0 10 0 (AA te) Baa 
D minu HiHiH BAH O1e 10 70.10 ,010 
when they should have been called imperfect reactions with forma- 
tion of parthenospores. A close examination, especially in the 
younger stages, will show that parthenospores develop from single 
gametes, and that the suspensor on only one side has a typical 
appearance, with what appears to be the suspensor on the opposite 
side frequently more or less rounded off and not closely adnate to the 
spore. The parthenospores themselves are often distinctly mis- 
shapen, but when the zygospores are small, as is true of those of 
species of Cunninghamella, it may be difficult to distinguish them 
