“…In hydrozoan cnidarians, however, neurons develop from non-epithelial, migratory stem cells, called i-cells, which are segregated during gastrulation (Gahan et al, 2016; Hager and David, 1997; Leclere et al, 2012; Miljkovic-Licina et al, 2007). Pharmacological inhibition of Notch signaling in adult Hydra , a hydrozoan cnidarian, revealed no effect on the numbers of adult neurons (Käsbauer et al, 2007; Khalturin et al, 2007), but this treatment did affect nematocyte differentiation and tentacle development (Käsbauer et al, 2007; Khalturin et al, 2007; Münder et al, 2013), defects that were also observed in Nematostella following pharmacological Notch inhibition (DuBuc et al, 2014; Fritz et al, 2013; Marlow et al, 2012). Hence, the role of Notch in tentacle morphogenesis and nematogenesis seems to be conserved in cnidarians, but its function in neural development requires further research across the phylum.…”