24 UNITED STATES NATIONAL MUSEUM BULLETIN 29 6 



Circulatory and Respiratory Systems 



Cirripedia in general have a lacunar circulatory system, with the 

 blood moving through lacunae or hollows within the body and mantle. 

 These lacunae have no real walls, and no heart has been described. 

 It appears that body movements cause the blood to circulate. 



Respiration is by diffusion through the body and mantle surfaces, 

 and extensions of these surfaces. No specific respiratory structures 

 such as gUls can be found. The extensions include the conical ventral 

 body processes, of which Lithoglyptes indicus and Berndtia purpurea 

 have two pair and Kochlorinopsis discoporellae has one pair; the dorsal 

 filamentary body processes in the family Cryptophialidae; and the 

 internal and external mantle flap-like processes in Trypetesa. 



Reproductive System 



The ovaries lie on the dorsal side of females of most species (except 

 T. lateralis, see section on the Mantle, page 14) . They lie in the mantle 

 spaces also occupied by blood sinuses and lacunae, immediately under 

 the horny disk of the mantle. Many fibers traverse the ovary, con- 

 necting the inner and outer cuticles. 



Oviducts generally arise near the anterior end of the ovaries and 

 open into the mantle cavity on both sides of the ventral thorax between 

 the point where the thorax meets the mantle posteriorly, and the 

 mouth cirri. The oviducts open into the more or less expanded atrium, 

 which in turn opens as a slit into the mantle cavity. 



The site of fertilization is not known, but the fertilized eggs are 

 retained in the mantle cavity untU hatched, and usually until freed 

 into the sea as cyprid larvae. The nauplius and metanauplius stages 

 are passed in the egg within the mantle cavity in most species. 



The Male 



The acrothoracican male is of reduced size, in total mass being 

 smaller than the cyprid larvae. The complete lack of a digestive 

 tract and feeding appendages precludes the intake of food, and the 

 maturation process is at the expense of larval food reserves. 



The features typically present in the male include a well-developed 

 single testis and a simple seminal vesicle, a naupliar eye, and paired 

 first antennae. In addition an extensible penis is present in most 

 species in very mature males. Various reflecting, opaque, reddish- 



