Aplacophora is a presumably paraphyletic taxon. This is a class of small, deep-water, exclusively benthic, marine molluscs found in all oceans of the world. All known modern forms are shell-less: only some extinct primitive forms possessed valves. The group comprises the two clades Solenogastres (Neomeniomorpha) and Caudofoveata (Chaetodermomorpha), which between them contain 28 families and about 320 species. The aplacophorans are traditionally considered ancestral to the other mollusc classes. However, the relationship between the two aplacophoran groups and to the other molluscan classes and to each other is as yet unclear.
Aplacophorans are cylindrical and worm-like in form, and most very small, being no longer than 5 centimetres (2 in); some species, however, can reach a length of 30 centimetres (12 in).

An illustrated outline filled in with a solid color(s), usually only black, and intended to represent the shape of an object without revealing any other visual details; a similar appearance produced when the object being viewed is situated in relative darkness with brighter lighting behind it; a profile portrait in black, such as a shadow appears to be.

a summons that commands the appearance of a party at a proceeding

Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. Signs are objective and externally observable; symptoms are the patients reported subjective experiences. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showing on a medical scan. A symptom is something out of the ordinary that is experienced by an individual such as feeling feverish, a headache or other pain or pains in the body.