SEGMENTATION
In some animals, the body is externally and internally divided
into segments or somites with a serial repetition of atleast
some organs. Segmentation can be of following two types
1. Metameric Segmentation
A segmentation that simultaneously divides body both
externally and internally is called metamerism or
metameric segmentation. This kind of segmentation is
found in annelids, arthropods and chordates.
2. Pseudometamerism
It is found in tapeworm, the body is divisible into parts or
segments called proglottides. They develop from the neck
but are not embryonic in origin. Such a repetition which
appears due to repeated budding is known as false
segmentation or pseudometamerism.