b. With a caudal process 5
3. a. Anterior end angular 4
on left side
b. Anterior end rounded Genus _Chlamydodon_
4. a. Dorsal striæ and cilia present, Genus _Orthodon_
ventral cilia longer
b. Dorsal striæ and cilia absent; Genus *_Chilodon_
posterior end not pointed
c. Dorsal striæ and cilia absent; Genus _Scaphidiodon_
posterior end pointed
5. a. Caudal spine with posterior 6
bristle-like cilia
b. Caudal spine without posterior Genus _Trochilia_
bristle-like cilia;
ventral cilia reduced
6. a. With pigment spot on anterior Genus _Ægyria_
angle
b. Without such pigment spot Genus _Onychodactylus_
c. Cilia on right edge only of Genus *_Dysteria_
greatly reduced ventral surface
* Presence at Woods Hole indicated by asterisk.