THE BURROWING BARNACLES (CIRRIPEDIA: ACROTHORACICA ) 7 



the apertural lips or opercula are separated from the head and flattened 

 separately if possible. The mouth field should be examined from several 

 angles, which sometimes can be accomphshed by roUing the head 

 area by moving the cover sUp, or by carefully lifting and redepositing 

 the head several times. 



If fresh or living material is available, studies of the musculature 

 and other organ systems can be undertaken by staining, clearing, and 

 mounting in balsam, and by making serial sections which are stained 

 and examined. 



Any males found associated with the females should be examined 

 in situ, before heating in KOH if possible, and notes should be taken 

 on their position and penetration of the female. They should then be 

 removed and studied separately in glycerin, or stained and mounted 

 in balsam. 



Larvae usually are treated along with the female, using the female 

 as a transfer vessel. 



Trypetesa lateralis has been kept aUve in shallow dishes of sea water 

 in a refrigerator for over a year. Although no noticeable growth occurred 

 under these conditions, the females reacted quickly to a touch by 

 withdrawing deeply into the burrow. 



The first few attempts at keeping the barnacles ahve in the labora- 

 tory involved leaving them with their commensal hermit crabs. It 

 soon became apparent that the barnacles were hardier than the hermit 

 crabs, and did not require hermit crabs in order to survive. Separate 

 vessels were allowed to evaporate to two-thirds volume, before distilled 

 water was added to the original level, without kilhng the barnacles. 

 Temperature fluctuations did not seem as deleterious to the barnacles 

 as to the crabs. Yet the crabs can be found in protected Uttoral zones 

 where the barnacles are not found. 



Orientation 



Orientation in barnacles is made difl&cult by their curled adult 

 configuration. It has been said that they stand on their heads and 

 kick food into their mouths with their feet. This is figuratively true 

 with both the orders Thoracica and Acrothoracica. From evidence of 

 comparative anatomy and embryology, the following orientation 

 terms can be designated, as they pertain to the order Acrothoracica. 

 AU descriptive matter pertains to the female unless otherwise stated. 

 The area where the mantle is cemented to the burrow is dorsal, 

 except in Trypetesa lateralis which is cemented on the right side. 

 The ventral surface of the body extends from above the mouthparts 

 onto the inner curvature of the thoracic cirri. The caudal appendages. 



