Anatomy & Physiology
The digestive system of euphausiacea consists of
two pairs of ostia that perforated their short heart. The stomach can be separated
into three parts the anterior part called the cardia, the posterior called the
pylorus and the mid-gut called the funnel. The cardias function is the primary
filter of the gut, the filtered food is then passed into the food channel which
is part of the pylorus. Although this anatomy does not differ greatly from the
rest of the Crustacea, it does lack a secondary filter giving a better
understanding of links between related taxa (Ullrich, et al. 1991).
The other unique euphausiacea characteristic is the
presence of photophores, these organs are responsible for the bioluminescence
present in almost all of the euphausiacea. These organs consist of a lens,
pigment cup, reflector and a mass of cells that reflect light. They are thought
to be associated with schooling and possibly mating displays (Ullrich, et al. 1991; Ruppert, et al. 2004).
Photo available at ; Euphausiacea summary |