While the reality of the taxon Turbellaria has been called into question lately, turbellarians are nevertheless the subject of active research by a sizable group of biologists. Turbellarians are relatives of the major groups of parasitic platyhelminthes - monogeneans, digeneans, and tapeworms - and most are free-living. Because the ancestors to the major parasitic groups would be classified as turbellarians, strict application of princi- ples of phylogenetic systematics dictates that the Turbellaria is not properly considered a separate taxon; i. e. , it is, in the parlance of systematics, a paraphyletic group. The relationships of turbellarians to other inver- tebrates are even more problematic than their relationships to other platyhelminthes; their relatively simple morphology has been variously interpreted as quintessentially primitive - meaning a turbellarian-like ances- tor would have given rise to most of the major groups of invertebrates - or as secondary simplification, meaning they would essentially be a dead-end group. Modern research on turbellarians covers a broad spectrum. Questions of phylogenetics have inspired ultrastructural studies; the simply structured nervous systems of turbellarians make them good subjects for neurophysiology; simplicity of their tissue structure and the limited number of cell types make them good subjects of embryological and regeneration studies; they are emerging as iIIJ. portant indicator species in ecolo- gy; and improvements in biochemical methodology have meant they are at last amenable - despite their small size - to molecular biological study.

Turbellarian platyhelminths (or, as they are known now among cladistic systematists, free-living Platyhelminthes) comprise a widely distributed assemblage of lower worms found in marine, freshwater, and even occasionally in terrestrial habitats. The phylum Platyhelminthes may be more widely known for its parasitic members since the major parasitic groups of the tapeworms, flukes, and their relatives are more speciose and have greater impact on everyday human life; but the turbellarians are more diverse and, as inhabitants of virtually any aquatic habitat, are more widespread as well. Many of the lower turbellarians are rather simple in morphology and have served as models for ancestors of the Bilateria, i.e., the bulk of the animal phyla. Others are quite complex organisms, especially in the morphology of their reproductive systems which are highly specialized. The majority are free-living in aquatic habitats but a number of interesting parasitic and commensal species are found scattered among the higher turbellarian taxa. But turbellarians are more than just taxonomic curiosities. They have served as illustrative models in research on a variety of basic life processes. For example, their high capacity for regeneration has made them the subject of a large literature in developmental biology, the occurrence of mixoploidy and other karyological oddities among turbellarians has been important in understanding evolution of the genome, and the fine structure and biochemistry of the nervous system in turbellarians is revealing important principles of the organization of so-called primitive neural systems.

The Time I Met My Jack Duluoz is a fictionalized reflection on one man's journey through San Francisco at night. Through found love, he is able to make his way home from a club, to an overlook of the bay, to a pier, and back to his hostel room after facing personal ordeals that he has never seen the sight of.