"These are little fish-like animals furnished with one or two fin-like organs on the body and a broad and usually bilobed caudal-fin. they are of small size and swim with great rapidity. They have hitherto been found principally in the North Sea and in the Mediterranean. The name of <em>Sagitta</em>, given to these animals, refers to their arrow-like appearance." &mdash; Goodrich, 1859

Sagitta

"These are little fish-like animals furnished with one or two fin-like organs on the body and a broad…