THE BURROWING BARNACLES (CIRRIPEDIA: ACROTHORACICA) 91 



mantle sac immediately posterior to the aperture. A secondary 

 reinforcing bar lines the dorsal interior of the mantle sac. Scattered 

 teeth, usually two- or three-pointed, but occasionally four-pointed, 

 stud the mantle. No orificial knob or attachment knob is present, 

 although a well-developed adhesive area is represented by a large 

 quantity of cemented exuviae, usually bearing two or more males. 



Figure 22. — Cryptophialus heterodontus, new species: a, female with males, side view, from 

 Tridacna maxima from Heron Island, Australia; h, female with male, side view, from 

 Distichopora nitida, from the Marshall Islands; c, d, e, opercular horizons of Heron Island 

 specimens, rostral end to right; /, mandible, Heron Island specimen. 



The mantle aperture is armed on both sides with an array of heavy 

 teeth which become progressively larger dorsally. These teeth bear 

 secondary teeth and hairs. A velum bearing the comb collar is promi- 

 nent on the ventral side of the aperture. The length of the aperture 

 of the type specimen is 0.3 mm. 



