Page:Journal of the Academy of Natural Sciences of Philadelphia (IA journalofacademy01acaduoft).pdf/11

Rh 

Character. Body free; furnished with fins for swimming; head distincy.

Character. Destitute of a gelatinous, horny, or calcareous shell.

Char. Jaws horny; eyes two; fins 1, 2, 3; branchia plumose, floating freely beneath the body, and grouped with the heart, around an oblong nucleus at the base of the tail.

The body is elongated, cylindrical, of a gelatinous, diaphanous consistence, and of a pale colour. Tail distinguised from it by a groove, one fourth the length of the body, compressed, more or less carinated, and laterally serrated, terminated by a lobed fin, and sometimes with a moniliform, elongated appendate. Eyes composed of a brilliant hyaline globule, supported by a small peduncle, which arises from a black concave or convex cup, placed at the junction of the rostrum with the body. Several small gelatinous points, before and above the eyes, serving probably to assist in retaining the molluscous prey in