IDENTIFICATION OF WHOLE MOUNT EMBRYO OF CHICK

 

Fig.1. Dorsal view ( X 14) of entire chick embryo having 4 pairs of mesodermic somites (about 24 hours incubation).

Identifying Characters:

• Area Opaca & Area Pellucida quite distinct.
• Primitive streak shortened to about half its original size & is restricted to the posterior end of area pellucida.
• Presence of 1-4 somites, representing the segmented mesoderm.
• Presence of head fold involving ectoderm & endoderm at the anterior tip of the head process.
• Neural folds well developed towards anterior end.
• Primitive streak in a reduced state. 

                   - Hence, the specimens seems to be a Chick embryo after 24hours of incubation.

Fig:2:Chick embryo after 48 hours of incubation.

Identifying Characters:

• Neural tube is differentiated into brain & spinal cord.
• Somites are 26 pairs.
• S-shaped heart is seen to have turned onto the left side.
• Presence of an enlarged telencephalon.
• Optic cups are prominent.

                           -Hence,the specimen seems to be a Chick embryo after 48 hours of incubation.

Fig:3:Chick embryo after 72 hours of incubation.

Identifying Characters:

• Paired cerebral hemisphere buldges  from the roof of telencephalon.
• Somites are 35 pairs.
• Appendages rudiments are present.
• Optic cups with distinct,closed retina & lenses.
• Head fold grows back & lies between 10-18 somites.
• Tail bud is at 90degree angle to the axis of posterior trunk.

                   -Hence,the specimen seems to be a Chick embryo after 72 hours of incubation.

Fig:4:Chick embryo after 96 hours of incubation.

Identifying Characters:

• Tail is segmented upto the tip of embryo.
• Eye pigmentation is very distinct.
• Caudal part of second arch distinctly elevated over surface.
• Presence of more than 44 somites.
• Length & width of wing bud & leg bud are almost equal.  
  

                -Hence,the specimen seems to be a Chick embryo after 96 hours of incubation.