THE CIRRIPEDIA. 257 



in position with those of Daphnia. No heart or other cir- 

 culatory organs are known to exist ; and it may be doubted 

 if the ovigerous fra?na of Lepas exert, as they have been sup- 

 posed to do, a branchial function. 



The nervous system consists of a pair of cerebral ganglia 

 situated in front of the oesophagus, and connected by long 

 commissures with the anterior of five pairs of thoracic gan- 

 glia, whence nerves are given off to the limbs. In the mid- 

 dle line the cerebral ganglion gives off two slender nerves, 

 which run parallel with one another in front of the stomach 

 and enlarge into two ganglia, whence they are continued to 

 a double mass of pigment, representing the eyes. From the 

 outer angles of the cerebral ganglion arise the large nerves 

 which proceed into the peduncle and supply the sac. These 

 appear to correspond with the antennary and frontal nerves 

 of other Crustacea; and Mr. Darwin describes an extensive 

 system of splanchnic nerves. 



Lepas, like the majority of the Cirripedia, is hermaphro- 

 dite. The vesiculae seminales are readily seen in fresh speci- 

 mens, as white cords distended with spermatozoa, which run 

 from the canal of the penis, into which they open, forward, 

 on each side of the body, to the prosoma, where they end in 

 dilated extremities, which are connected with a multitude of 

 ramified caeca forming the proper testis. 



The ovaries are ramified tubes provided with caecal dila- 

 tations, and lodged in the peduncle. The oviducts pass into 

 the body, and, according to Krohn, terminate in apertures 

 situated on the basal joint of the first pair of cirri. 1 Two 

 " gut-formed" glands, as they are termed by Darwin, lie, 

 one on each side of the stomach, and are probably accessory 

 glands of the reproductive organs, analogous to those which 

 secrete the walls of the ovisac in the Copepoda. 



The mode of exit of the ova from the ovary is not cer- 

 tainly known, nor is the place of their impregnation ascer- 

 tained ; but they are eventually found cemented together by 

 chitin into large lamella?, which adhere to the ovigerous 

 frrena, and, ordinarily, at once strike the eye when the ca- 

 pitulum of a Cirripede is opened. 



Yelk division is complete, and the embryo attains to its 

 earliest larval condition within the egg. If a series of the 

 fresh ovigerous lamella? be taken and pulled to pieces with 



i The position of these apertures corresponds with that of the openings, 

 supposed to appertain to the shell-glands in Limnadia and Apus. 



