474 DISCOVERY REPORTS 



erect part, below the opesia, may be annulated. These annulations are undulations of 

 the whole punctate wall, and must not be confused with the rings sculptured on the 

 surface of the wall in A. anguina and A. recta. Zooeciules and appendages are present, 

 as in A. truncata (see Harmer, 1926, p. 197), and the zooecia have the truncate distal end 

 and oblique operculum of that species. 



British specimens of A. truncata, including two preparations from Landsborough's 

 material from Arran (99.7.1.566, 567, presumably part of the type-material), differ 

 from these Ascension Island specimens in various ways (cf. Plate XIII, figs. 1 and 2). 

 The zooecia are smaller and more slender. The erect part is very straight and markedly 

 tapering proximally, as shown in Hincks's figures (1880, pi. i, figs. 8-1 1 ; pi. ii, fig. 3). 



Fig. 58. Aetea curta Jullien. St. 1, Ascension Island. A. Dry specimen, seen by reflected light. Erect parts 

 much foreshortened. B. One zooecium and parts of adjacent ones in an oblique frontal view. 



ops. opesia, si. zooeciule. 



The opesia usually occupies less than half the length of the erect part. The encrusting 

 part is narrower than the erect part, threadlike for the greater part of its length, and 

 usually even longer in proportion to the erect part than is that of the Ascension Island 

 specimens. There is no trace of annulation. I have seen neither zooeciules nor appen- 

 dages in British specimens, but they might be found if more material were examined. 

 The relative lengths of the various parts vary to some extent probably with conditions of 

 growth, but the differences in shape and absolute size make the Ascension Island form 

 clearly distinguishable from typical British A. truncata. 



On this argument many of the specimens from various parts of the world, recorded 

 as A. truncata, would be distinct from the British species, and I think this is probably 

 so. Marcus's figure of his A. truncata shows most of the features of the Ascension Island 

 species. 



It remains to consider whether the Ascension Island form can be identified with any 

 described species. Jullien described A. curta as having the " pedoncule " (i.e. the tubular 



