Ascidians are sister groups of vertebrates, and their cosmopolitan species, Ciona intestinalis Type A has been used for developmental biology, evolutionary biology, and genome sciences. In contrast, the nervous and endocrine systems of Ciona largely remained unknown. Over the past fifteen years, Ciona peptides, their cognate receptors, and the biological roles in the processes of morphosis and ovarian follicle development. These findings pave the way for investigating the nervous and endocrine systems of Ciona and the evolutionary processes of these systems in chordates. In this review, we provide the overview of Ciona peptides, receptors, and biological functions.

In this paper, the biomimetic motion of a soft body of a live creature is introduced. The motion of a creature without a skeletal structure, such as mollusks and annelids, is an example. The movement of cilia and flagella and peristalsis of the digestive tract are also other good examples of soft motions. In order to mimic such biological motions, soft materials have been attracting attention in recent years, which have been treated in the field of the soft robotics. This paper describes the characteristics of soft structures, comparing them with robots with joints, such as industrial robot hands. Some examples of the materials for this purpose are introduced, and among them, magnetic soft structure, which could be actuated by an external magnetic field, is described in detail. Artificial cilia array is presented as an example of biomimetic motion with magnetic soft material. In this cilia, asymmetric beating motions and metachronal waves, which are observed in biological cilia motion, are described. As another example, a crawling motion, which is expressed as a traveling wave in the body, is demonstrated. Through these examples, we discuss the current status and future of the biomimetic engineering of these soft motions.