THE BURROWING BARNACLES (CIRRIPEDIA: ACROTHORACICA) 43 



The segment count for the cirri follows: 



Terminal 



cirrus: 1 2 3 4 5 



Ramus: ant.* post.** ant. post. ant. post. ant. post. ant. post. 



Segments: 13 9 18 19 28 32 34 38 36 39 



♦Anterior. **Posterior. 



The thorax is articulated in several places, essentially corresponding 

 to a segment for each cirrus. An incomplete, weak, reinforcing ring is 

 seen just anterior to the entire set of terminal cirri. 



The male: The males are rare, attached to the exuviae of the 

 female, and bear the usual paired antennules without long stalks 

 (fig. 3j). A well-developed penis is coiled within the body, but its rela- 

 tionship to the other organs is uncertain. Scattered clusters of cells 

 of apparent glandular function are seen, and there is a curious rounded 

 projection from the end of the body opposite the point of attachment. 



The LARVAE: The larvae are retained to the cyprid stage (fig. 3k). 

 The cyprid is typical, with a pair of antennules, a simple naupliar 

 eye and a pair of cyprid eyes, six pairs of bristle-bearing swimming 

 appendages, and a caudal furca probably analogous to the caudal 

 appendage. A small, yellowish sphere with pointed projections was 

 seen in the midst of a glandular mass in the anterior thoracic region. 

 No function is ascribed to this, although it is conceivably analogous 

 to the "yellow organ" of the males. No carapace ornamentation was 

 seen. 



Relationship: The only really effective point of differentiation 

 between the genera has been the number of cirri and the presence or 

 absence of the caudal appendages. Using this criterion, this species is 

 definitely in the genus Weltneria. The appearance of the mantle 

 aperture bears striking resemblance to Berndtia nodosa Tomlinson 

 (1967), however. Berndtia is differentiated from Weltneria by the lack 

 of a caudal appendage in the former. All specimens of this species 

 examined showed clearly a well-developed caudal appendage. 



The burrow : The shape of the burrow aperture, as viewed from the 

 outside, varies with the local conditions, especially the presence of 

 algae and other organisms. The basic shape is that of a typed apos- 

 trophe, which is typical of the order. 



Figure 3n shows a set of four burrow apertures averaging 1.15 X 0.45 

 mm in length and width. The burrow apertures 1 and 2 are in clean 

 shell, while 3 and 4 are overgrown with algae. In the former two the 

 original attachment site can be seen at the pointed end of the slit, 

 which possesses a microscopic shelf of material upon which the larval 

 antennules can be discerned in some specimens. It is difficult to 



