Abstract

The anatomy and histology of the nervous system in the giant mussel Choromytilus chorus (Mytilidae), commonly known as “Choro zapato” in Chile were studied. Specimens of C. chorus in phase of first sexual differentiation (40 mm of lenght valvar) and broodstock adult of 120 mm were collected in the soft-bottom intertidal of Laraquete Couve, Chile (37°09'S; 37°11'O). The juveniles were used for analysis histological and the adults for a macroscopic description of the anatomic structures (120 mm) through of observation low stereoscopic magnifier. The mussels intended for histology were immersed in formalin at 10% for 48hr, later on dehydrated and embedded in paraffin for making seriated cuts in plane sagittal and transversal later the representatives seriated cuts of each plane were stained with hematoxylin-eosin. In the macroscopic analysis, it was observed that nervous system is constituted for three pairs of ganglia of color orange of little size (20-40 mm): cerebral, pedal and visceral, located in the zone anterior, middle and posterior the specimen, respectively, associated with different tissue of the animal. In the histological analysis, it was observed many type de cells inside the ganglia, cells neurosecretory, granulated and glial. The three pairs of ganglia through of their neurosecretions could be involving in regulating several physiological processes in the mussels.