Provide definitions/explanations for the following terms:
$(i)$ Cephalochordata
$(ii)$ Pseudocoelomates

(N/A) $(i)$ Cephalochordata: These are chordates in which the notochord extends from head to tail region and is persistent throughout their life. Examples include $Branchiostoma$ (Amphioxus or Lancelet).
$(ii)$ Pseudocoelomates: These are animals in which the body cavity is not lined by mesoderm; instead,the mesoderm is present as scattered pouches in between the ectoderm and endoderm. Such a body cavity is called a pseudocoel,and the animals possessing them are called pseudocoelomates. Example: $Aschelminthes$ (Roundworms).