THE BURROWING BARNACLES (CIRRIPEDIA! ACROTHORACICA) 131 



with many layers of cemented exuviae, where the female is attached to 

 the burrow wall. 



Within the lips of each side is a row of scaly teeth, which become 

 thin in places along its length. This row of teeth presumably helps to 

 prevent the intrusion of foreign matter or animals. 



I could find no dorsoanterior mantle flap, as Utinomi describes, 

 filled with egg masses. None of my specimens were gravid. Since the 

 mantle flap of Trypetesa lateralis extends ventro anteriorly and is too 

 solid to admit egg masses, the mantle flaps are not considered homo- 

 logous or analogous. No lateral bar is present.- 



The body is small as compared with the size of the mantle sac in 

 mature females. The segmentation appears to be of six segments as 

 described by Utinomi. 



The head is quite pointed and scaly on the apex. A row of hairs of 

 variable length extend along each side of the head. This array of hairs 

 would probably be an effective barrier against intrusion, but it is not 

 the "comb collar" as Utinomi suggests (1964, p. 123 and p. 128). A 

 genuine comb collar could not be found, and presumably does not 

 exist in this species. Its function is probably assumed by the row of 

 scaly teeth and fine hairs lining the apertural lips as already stated. 



The labrum is not well developed. 



The mouthparts are aberrant. The mandibles are simple, beaked, 

 and heavily chitinized. No additional teeth or hairs were noted. 



A mandibular palp could not be found, and Utinomi does not 

 describe one. 



A pair of first maxillae are located immediately behind the man- 

 dibles. They each have two heavy teeth separated by a distinct 

 notch. Very long, straight apodemes extend from their bases to a 

 common area dorsoposteriorly. The apodemes seem to be associated 

 with a separate chitinized structure arising from the dorsal surface 

 of the head. I postulate that these latter are additional reinforcing 

 struts and that the first maxillae do a large share of the mastication. 



The second maxillae are simple lobes behind and between the 

 first maxillae. 



The "mouth cirri," are long, plump, weakly chitinized, and covered 

 distally with short and fine hairs. Two rami are mounted on a protopod 

 of one or two segments, the number depending on the designation of a 

 fold or crease in the cuticle near the distal end. Utinomi described it as 

 one-segmented, and I will concur. 



The three pairs of terminal cirri are uniramous and much shorter 

 than acrothoracicans of other families. The first and third terminal 

 cirri are approximately of equal length, and slightly shorter than the 

 second pair. Each consists of four segments. The first two pairs of 

 terminal cirri bear a protuberant "button" or "cushion" on, the distal 



