Let us learn about the comparison of ciliary mode between branchiostoma, ascidia and balanoglossus.

Comparison # Balanoglossus:

1. Internal food-collection, i.e., food is collected inside the body.

2. Microphages.

3. Wheel organ produces a flow of water-current which is drawn into the mouth.

4. Velum with velar tenta­cles control the entry of water-current into mouth.

5. The feeding current follows the following course:

Mouth → Pharynx → Pharyngeal gill-slits → Atrium → Atriopore → Exterior

6. Cilia present in gill-bar beat to drive the water- current into the atrium through the gill-slits and thus maintains a con­stant water-current thro­ugh mouth.

7. Food-particles are entan­gled by the sticky secre­tion of the mucous cells of the endostyle lying on the floor of the pha­rynx.

8. The mucus-entangled food-particles are driven by the cilia of endostyle as a food-rope along the peripharyngeal ciliary grooves to the epipha­ryngeal groove from where food-cord passes to oesophagus.

9. The entry of the large particles are prevented by the buccal cirri around mouth.

10. Afferent and efferent nerve-fibres are held to control the ciliary-beating and regulate the water-current.

11. The receptor-organs present over the velum and atrium, taste and regulate the nature of water-current.

12. If the water-current con­tains any toxic sub­stance, the atriopore becomes closed and the pharyngeal-muscle con­tracts and the water- current is regurgitated.

Comparison # Ascidia:

1. Internal food collection

2. Microphages.

3. No wheel organ. Exter­nal water-current direc­tly enters into the mouth.

4. Same as in Branchios­toma.

5. Same as in Branchios­toma

6. Same as in Branchios­toma.

7. Food-particles from the feeding-current are en­tangled by the mucus, secreted from the glan­dular tracts of endo­style.

8. The mucus-entangled food-particles move upward from endostyle along the peripharyn­geal ciliary grooves and then reach the dorsal lamina from where food-cord is pushed back into oesophagus.

9. The tentacles at the base of the oral siphon are held to obstruct the entry of large particles.

10. Same as in Branchios­toma.

11. The receptor-papillae on the stigmata, may check the water- current.

12. Unwanted water- current is forcefully expelled by the closing of one siphon, and the subsequent contraction of the body muscula­ture.

Comparison # Balanoglossus:

1. External food-collection, i.e., food particles are trapped outside the body.

2. Microphages.

3. Due to external food- collection, there is no need of water-current toward mouth.

4. Muscular tip of the collar over the mouth regulates the feeding- current into mouth.

5. The feeding-current follows the following course:

Mouth → Pharynx → Pharynx → Pharyngeal gill-slits → Exterior

6. Cilia of gill-bars beat to maintain a constant water-current via mouth and pharyngeal gill-slits to the exterior.

7. As food-collection is external, food-particles are entangled outside the body by the mucus, secreted by proboscis. The mucus-coated food- particles directly pass into the mouth by cili­ary action.

8. The externally-collec­ted food-particles pass directly to the oesopha­gus via the ventral digestive part of the pharynx. There is no endostyle and epipha­ryngeal groove.

9. The muscular tip of the collar can be folded over the mouth, to pre­vent the entry of large particles.

10. Nerve-fibres reflected in the collar epithelia, are held to control the ope­ning of the mouth by the muscular fold of collar.

11. Sensory-cells at the edges of pre-oral ciliary organ at the base of the proboscis act as chemo-receptor organ and taste the nature of feeding-current

12. No such regulatory mechanism is known.

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