Full text of MNL contribution: Research news: 1. Note on identity of mutants. A mutation that arose at the Jackson Memorial Laboratory and was provisionally named footless, was tested against our mutant, limb deformity, ld. The results were: (1) ld/ld x footless homozygotes, 23 young, all abnormal; (2) ld/ld x footless heterozygotes) (3) +/ld x footless homozygotes) 18 abnormal: 41 normal. It is concluded that footless is identical to or allelic with ld. Within the ld stock, ld/ld shows a viability of approximately 60-70% of normal (+/ld x ld/ld gave 63 ld/ld: 91 +/ld; +/ld x +/ld gave 32 ld/ld: 169 +/ld or +/+). Therefore, the low ratio of abnormals in crosses (2) and (3) above may possibly indicate that footless is a more extreme allele at the ld locus. (Cupp)