Ledges very small; body long, Genus _Amphisolenia_
needle-like
5. Ledge of longitudinal furrow 6
extends to posterior end
Ledge of longitudinal furrow Genus _Dinophysis_
does not extend to posterior end
(Recorded by Peck ('93-'95) as very abundant at Woods Hole
and in Buzzards Bay.)
6. Ledge is continued dorsally to Genus _Ornithocercus_
the cross-furrow