A little way beneath the lower or anterior pair of limbs, the thorax is abruptly bent, and becomes confluent with the lower internal parts of the whole animal. Here, the very delicate membrane of chitine which lines the sack or tube, extending from the external orifice, can be seen to be continuous, as in all Cirripedes, with the outer tunic of the thorax. Within the thorax, there are some longitudinal muscles, without transverse striæ, which, I believe, enter the short limbs, but not the abdomen, as I infer from the latter not being everted when they are pulled. At their lower ends these muscles terminate abruptly, and from being contracted are often a little enlarged. They extend a short way beneath the lower pair of limbs, and are, I suspect, attached to the outer integument of the animal, near the base. After the most careful dissection of very many specimens, and their examination in many different methods (as by caustic potash, &c.), I can venture positively to assert that there is no vestige of a mouth, or masticatory organs, or stomach: I did not see any anus, but I will not affirm that such does not exist. In the upper part of the animal, lying under the superficial muscles, and close beneath the upper line of their attachment, I found in all the specimens, an eye, of a pointed oval form, rather less than 11/12,000ths of an inch in diameter, formed of an outer capsule, lined with purple pigment-cells, and surrounding, as it appeared, a lens. The eye is not introduced in fig. 9, for I could not see it, except by dissection, and therefore do not know its exact relative position.