The respiratory apparatus of Balanoglossus comprises:
The branchial sacs that open out through gill-pores.
The branchial portion of pharynx bearing gill-slits.
Branchial pharynx.Two lateral longitudinal parabranchial ridges divide the pharyngeal cavity into a ventral digestive portion and a dorsal respiratory or branchial portion.Dorso-laterally,on each side,the branchialportion is perforated by a longitudinal series of numerous U-shaped opening, the gill-slits.Their number varies and increases as the animal growa older.To start development a gill-slit is a broad oval slit. Later, a hollow projection of dorsal pharyngeal wall, called tongue bar,grows into the making it U-shaped.A tongue bar is connected with adjacent gill septa by short transverse or horizontal connections, the synapticula. The development and arragement of gill-slits is identical with that found in Branchiostoma.The gill-slits are richly lined by cilia, called lateral cilia.
The branchial sacs that open out through gill-pores.
The branchial portion of pharynx bearing gill-slits.
Branchial pharynx.Two lateral longitudinal parabranchial ridges divide the pharyngeal cavity into a ventral digestive portion and a dorsal respiratory or branchial portion.Dorso-laterally,on each side,the branchialportion is perforated by a longitudinal series of numerous U-shaped opening, the gill-slits.Their number varies and increases as the animal growa older.To start development a gill-slit is a broad oval slit. Later, a hollow projection of dorsal pharyngeal wall, called tongue bar,grows into the making it U-shaped.A tongue bar is connected with adjacent gill septa by short transverse or horizontal connections, the synapticula. The development and arragement of gill-slits is identical with that found in Branchiostoma.The gill-slits are richly lined by cilia, called lateral cilia.
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