46 LEPADIDvE. 



soria, minute spiral univalves, and often of the larvae 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 (t. 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 con- 

 tractions of the peduncle. 



Nervous System and Organs of Sense. — In most of the 

 genera, there are six main ganglia, namely, the supra- 

 cesophageal, and five thoracic ganglia ; but in Pollicipes 

 mitella there are only four thoracic ganglia. Of these, 

 the first thoracic or infra-cesophageal ganglion is con- 



