Study of Fish : Observation of Fish Bones.

 

Practical Name: Observation of Fish Bones. 

                     Fig: Pectoral Glide.

Characteristics:

1. Supra cleithram and cleithram are present above the thoracic spine.

2. It contains the scapula coracoid and Meso-coracoid.

3. Post cleithrum is present in its posterior part.

4. A row of proximal pterygiophores is located along the scapula.

 

                                                                   Fig: Gill Arch.

Characteristics:

1. Its shape is curved like a bow or English letter ‘S’.

2. They form the strong axis of the gills.

3. They carry gill rakers.

4. They are attached to the gill lamella.

5. They are long and smooth.

 

 

 

                    Fig: Operculum.

Characteristics:

1.  The bone is the largest, broadly triangular, flattened and slightly curved.

2.  Its surface is convex and ridged. Its posterior edge is crescentic.

3. There is a blister on the distal side of the bone.

4. A condyle exists at the tip of the bone to connect with the skull

5. It is the bone of the opercular region.

 

                                                                    Fig: Pre-operculum.

Characteristics:

1. The bone is flat and curved like a sickle.

2. It is concave towards the base and convex towards the surface.

3. There are several foramina on the surface.

4. Its front side is pointed and back side is wide.

5. The bone is located in the operculur region.

 

                    Fig: Supra Cleithrum.

Characteristics:

1. The bone is curved and sword-like.

2. One side of the bone is convex and the other side is concave.

3. Its posterior end is narrow and anterior end is wide and the middle is flattened.

4. The bone is attached to the cleithram.

5. The bone is located in the pectoral region.

                                                                    Fig: Post-cleithrum.

Characteristics:

1. The bone is long, narrow and rod-shaped.

2. Its two ends are pointed and the middle is slightly curved.

3. The lower medial region of the bone is slightly thickened and flattened.

4. It lies behind the cleithram.

5. It is the bone of the pectoral region.

 

 

 

            Fig: Sub-operculum.

Characteristics:

1. The bone is like a flat sword.

2. Its front end is pointed and the back end is quite wide.

3. Its surface is convex and upper side is concave.

4. The bone is located in the operculur region.

5. Some of its parts are attached to the front of the inter-operculum.

 

                                                               Fig: Inter-operculum.

Characteristics:

1. The bone is curved and the anterior end is narrow and the posterior end is broad.

2. Beside the narrow end is the articular facet.

3. A foramen exists at the wide end.

4. A deep groove is located on its distal side.

5. It is the bone of the opercular region.

 

 

                        Fig: Cleithrum.

Characteristics:

1. Bones are plow shaped or crescent shaped.

2. Its front end is pointed and the back end is wide.

3. A ridge exists on the surface of the pointed end.

4. The distal end of the bone has deep grooves into which the muscles is attached.

5. It is the bone of the pectoral region.

 

                                                            Fig: Pharyngeal bone with teeth.

Characteristics:

1. The bone looks almost triangular in shape.

2. It bears teeth on the surface.

3. Each tooth has a large opening in front.

4. It is attached posteriorly with the cleithrum.

     

                                                                     Fig: Quadrate.

Characteristics:

1. The bone is triangular in shape and looks like a fan.

2. It has two condyles at its anterior end.

3. The bone bears a ridge at the end.

4. It is attached to the angular bone by two condyles.

5. The bone is located in the mandibular region.

                                                                  Fig: Hyomandibular.

Characteristics:

1. The anterior end of the bone is wide and the posterior end is narrow.

2. It has two dense condyles at the broad end and a knob-like condyle at the convex side.

3. Bears a ridge on the ventral surface.

4. Its shape is like a rifle butt.

        

                                                         Fig: Typical caudal vertebra.

Characteristics:

1. Both ends of its centrum are concave.

2. At the top, the neural arches meet to form the neural canal.

3. Pre and post zygapophyses are present.

4. The two haemal arches meet downward to form the haemal duct.

 

                                                             Fig: Urohyal.

Characteristics:

1. The bone is almost triangular.

2. It is formed by three articular bones arranged parallel to each other.

3. It looks more like an inverted ‘T’ or a plane.

4. Its posterior end is broad and bifurcated and forked.

5. Condyle present at narrow anterior end.