The larvae of Emplectonema sp. 1 are easily recognizable as hoplonemertean larvae. They have 2–3 pairs of sub-epidermal eyes. One pair is anterior and conspicuous (Iwata 1960 reports this single pair, only). Additional eyes may be pigment patches and are situated near the cerebral organs, one large pair narrowly spaced and the other smaller pair near the anterior lateral cerebral organ region. The larvae have an apical tuft and posterior cirrus. What makes these larvae easy to recognize as the larvae of E. sp. 1 is that they are green. Adult E. sp. 1 are dark green dorsally and pale green ventrally (right) and their larvae exhibit similar coloring. Although the NE Pacific Emplectonema is commonly identified as E. gracile, DNA sequence data suggest that it is distinct from the Atlantic E. gracile. The early development of E. gracile from Akkeshi Bay, Hokkaido, Japan (which may be a different species than the one in the NE Pacific) has been described (Iwata 1960), but there is no mention of the brilliant green color we observed.