The mountain brook lamprey (Ichthyomyzon greeleyi) has no previous embryological description even though the lamprey's primitive developmental patterns are of value to evolutionary biologists. This research describes visible developmental processes of the mountain brook lamprey from the unfertilized ovulated egg to the release of ammocoete larvae into the field. In-vitro fertilization was the process used to produce viable embryos after strip spawning. This process successfully produced about 4000 embryos for descriptive observation. Embryological and larval developmental stages were named using criteria defined for Lampetra reissneri. The findings conclude that the timing of early developmental events is similar to that of other lamprey species.
