Dr. Lacalli's research involves the embryology and larval forms of marine invertebrates: principally, the development of the nervous system and the formation pattern in these organisms. His work has included theoretical, computer-based studies of how pattern and formation appear de novo in embryos as they develop, and microanatomical studies (primarily, via serial electron microscopy) of the developing nervous system in simple invertebrates near the evolutionary stem from which vertebrates, with their advanced nervous system, evolved. The process developed by Lacalli enabled an image of the whole body of their specimens in one micrograph, a relatively rare achievement and one which enabled him to analyse the nervous system in far more detail than was previously possible. This fonds contains an extensive collection of the electron micrographs taken by Lacalli, together with research notes, offprints, and other documentation relating to his research activities