ABSTRACT
Introduction Collectively, hagshes are among the earliest extant members of the vertebrate lineage. Although there have been multiple reports detailing the histology and gross morphology of various tissues, a comprehensive atlas
Introduction ........................................................................................................ 1 Tissue histology .................................................................................................. 2
Integument ..................................................................................................... 2 Sensory barbels .............................................................................................. 4 Dental plate .................................................................................................... 5 Dental muscle (pharyngeal muscle) ......................................................... 10 Somatic muscle ............................................................................................ 10 Intestine ........................................................................................................ 12
Foregut ..................................................................................................... 14 Hindgut .................................................................................................... 16
Liver .............................................................................................................. 17 Gall bladder .................................................................................................. 19 Renal system ................................................................................................ 20 Gill ................................................................................................................. 23 Cardiac tissue and associated structures ................................................. 26 Slime glands ................................................................................................. 29 Reproductive organs ................................................................................... 30
Methods ............................................................................................................. 33 Tissue perfusion and xation .................................................................... 33 Light microscopy ......................................................................................... 34 Scanning electron microscopy ................................................................... 34 Transmission electron microscopy ............................................................ 34
Acknowledgments ........................................................................................... 34 References ......................................................................................................... 35
of the hagsh that includes gross morphology, histology, and electron microscopy has never been created before. This chapter will provide a source for understanding the fundamental histology of cells and tissues in the Pacic hagsh (Eptatretus stoutii). By combining physiological studies with the described anatomy, we will be able to better elucidate the evolution of physiological and morphological traits.
