THE BURROWING BARNACLES (CIRRIPEDIA: ACROTHORACICA) 47 



The mantle is reinforced internally by two thickened rods projecting 

 posteriorly dorsal to the head, between the middle of the aperture and 

 the horny knob area. No separate external lateral bars of scaly 

 appearance were found. 



The operculum is armed with many extremely short teeth and very 

 short hairs. Almost all of the teeth have a single point. The ventral 

 (carinal) end of the aperture bears the typical comb collar on a velum 

 which apparently can be moved in and out of the apertural area. 



Figure 5. — Lithoglyptes indicus Aurivillius, 1892, from the Red Sea: a, female with embedded 

 male, side view, most of terminal cirri missing; b, mandible; c, mouth (first) cirrus; d, 

 caudal appendage. 



The head bears a row of short hairs, and has a coating of fine 

 granulations. 



The mouthparts are typical of the genus. A shield-like labrum 

 forms the top of the mouth field, followed posteriorly by a pair of 



