THE CIRRIPEDIA 



and have two unsegmented rami. In Alcippe the last three pairs 

 of cirri are uniramous. 



In many Pedunculata a membranous process ("filamentary 

 appendage," Darwin) grows out from the side of the body just 

 below the origin of the first cirrus. In Conchoderma similar 

 appendages are also attached to the peduncles of some of the 

 cirri, and in that genus and in Pollicipes others spring from the 

 sides of the prosoma. These processes may be occupied internally 

 by diverticula of the testes. In many Balanidae a setose plate is 

 produced from the outer side of the peduncle of the third pair of 

 cirri, and projects half-way across the dorsal surface of the body. 

 In Cryptophialus two pairs of filamentary processes spring from the 

 dorsal surface of the body. It seems possible 

 that some of those appendages which are attached 

 to the peduncles of the cirri or in the neigh- 

 bourhood of their articulation to the body may 

 be of the nature of epipodites. In many Cirri- 

 pedia a fold of the integument projecting into 

 the mantle-cavity originates on each side of the 

 cephalic region at the point where the mantle 

 ioins the body. In the Pedunculata these folds, 

 the " ovigerous frena " of Darwin, usually serve 

 for the attachment of the egg- masses, and are 

 equipped for that purpose with knobbed spines. 

 In the Verrucidae they are absent, but in the 

 other Operculata they are represented by large 

 plicated membranes no doubt branchial in function. 



Alimentary System. The stomodaeum appears, 

 is a rule, to form only the narrow oesophagus, 

 the large stomach being without a cuticular lining, 

 In some Acrothoracica (Cryptophialus), however, 

 a triturating apparatus is developed from the 

 inner end of the oesophagus, where it enters the 

 stomach, consisting of two opposed horny discs carrying teeth and 

 several rows of setae. The anterior part of the stomach generally 

 gives off a number of large "hepatic" caeca (Fig. 67, L), while 

 ramifying tubules forming the so-called " pancreatic glands " clothe 

 the posterior part and open into it by numerous small apertures. 



In Alcippe, among the Acrothoracica, the rectum and anus are 

 absent, and the ramified hepatic caeca radiate from the stomach 

 into all parts of the body. 



Circulatory System. No heart is present in any Cirripede, and 

 the lacunar channels in which the blood circulates are, for the most 

 part, ill-defined. The most important arid constant is the " rostral 

 sinus" (Fig. 64, s.ro) lying on the rostral side of the adductor 

 scutorum muscle. It has a pair of valves at its lower end where 



FIG. 68. 



Andasma fjtml uxla. 



v- the 

 and the reduced 



Gl 



