Southern board their distribution of Atlantic and Indian Oceans in region of Antarctic Convergence. Some authors remarke euryhalinity of this genus. In spite of the small sizes this genus has that the important economic significans. It is known often occurence of with these species in stomachs of plankton-eating fishies. Calocalanus, small copepods 0.36 to 1,50mm of size.
Body is oval or elongate form.
Head thoracic segment are fused. Fourth and fifth thoracic segment are separated. Genital segment is sometimes globulus and almost always has two easily visible spherical spermathecae. Anal segment of male is three-two times as long as the previous one. Anal segment of the male is well developed.