Approximately 11.4% of homozygous Sema-2a^ex59 hemisegments exhibit abnormal v'ch1 projection, with the axon mis-projecting anteriorly and joining the inter-segmental nerve instead of the segmental nerve. In most cases of v'ch1 mis-projection, the axon contacts the cell bodies and axons of nearby lateral cluster neurons, lesA and 1daA, which are located anterior and slightly internal to the v'ch1 cell body. In a small number of defective hemisegments, the v'ch1 axon bifuricates sending its axon both anteriorly to the intersegmental nerve and ventrally to join the segmental nerve. A second, less frequent defect is observed whereby one or more axons of the lateral cluster sensory neurons misproject ventrally, joining the v'ch1 axon and the segmental nerve, instead of the intersegmental nerve. Mis-projections of dorsal cluster sensory neurons are also observed in homozygous Sema-2a^ex59 mutants. One or more axons of dorsal cluster neurons either mis-projects posteriorly or loops anteriorly in the dorsal region before joining the intersegmental nerve in its normal position in the lateral region.

Approximately 18.3% of Sema-2a⁰³⁴⁷⁴/Sema-2a^ex59 hemisegments exhibit abnormal v'ch1 projection, with the axon mis-projecting anteriorly and joining the inter-segmental nerve instead of the segmental nerve. In most cases of v'ch1 mis-projection, the axon contacts the cell bodies and axons of nearby lateral cluster neurons, lesA and 1daA, which are located anterior and slightly internal to the v'ch1 cell body. In a small number of defective hemisegments, the v'ch1 axon bifuricates sending its axon both anteriorly to the intersegmental nerve and ventrally to join the segmental nerve.

The ISNb makes normal contact with muscle 12 and then extends ectopic connections dorsally and laterally into muscle 8. Ectopic connections are also observed for the transverse nerve into ventral muscles 7,6 or 13. The SNa stops abruptly at muscle 5, does not innervate muscle 8 but makes increased contact with muscle 5.