a distinct organ, like the closed tube in certain Annelids. Occasionally, I have seen one imperfect epithelial bag or tube within another and later-formed one. Digestion seems to go on at the same rate throughout the whole length of the stomach; if there be any difference, the least digested portions lie in the lower and narrower part. The prey, consisting generally of crustacea, infusoria, minute spiral univalves, and often of the larvæ of Cirripedes, is not triturated: when the nutritious juices have been absorbed, the rejectamenta are cast out through the anus, all kept together in the epithelial bag, which is excluded like a model of the whole stomach, with the exception of that part coated by the bell of the oesophagus. I have sometimes thought that the bag was formed so strong, for the sake of thus carrying out the excrement entire, so as not to befoul the sack. I believe Lepas can throw up food by its oesophagus; at least, I found in one case, many _half-digested_ small Crustaceans in the sack, and others of the same kind in the stomach. _Circulatory System._--I can add hardly anything to what little has been given by M. Martin St. Ange: like others, I have failed, as yet, in discovering a heart. The whole body is permeated by channels, which have not any proper coat: there is one main channel along the ventral surface of the thorax, dividing and surrounding the mouth, and giving out branches which enter the inner of the two channels in each cirrus: as Burmeister has shown, there are also two channels in the penis. There are two dorso-lateral channels in the prosoma, which are in direct connection with the great main channel, running down the rostral (_i. e._, ventral) side of the peduncle. This latter main channel branches out in the lower part, and transmits the fluid through the ovarian tubes, whence, I believe, it flows upwards and round the sack, re-entering the body near the sides of the adductor scutorum muscle. The main rostral channel (or artery?) in the uppermost part of the peduncle, has a depending curtain, which, I think, must act as a valve, so as to prevent the circulating fluid regurgitating into the animal’s body during the contractions of the peduncle.