Complex sentence: For instance, in the 19 day embryo rat spinal cord, at least 17 different subclasses of interneurons with ipsilateral axon projections and 18 types of commissural interneurons have been identified on the basis of morphology and location.
Split into simpler sentences: For instance, in the spinal cord of a 19 day embryo rat, at least 17 different subclasses of interneurons with ipsilateral axon projections were found. In addition, 18 types of commissural interneurons have been identified on the basis of morphology and location.