298 Southern Cross. 



added so much to our knowledge of the group ; it was he who 

 in 1893 (1 p. 281) first called attention to the presence, in some 

 Arctic actinians then under observation, of special "Brutraumen" 

 quite distinct and separated from the coelenteron. 



External characters. — Like the preceding species all the specimens 

 are greatly contracted. The colour, when living, as noted on 

 collectors' labels, was light red (large specimens) and white (small 

 specimens), but all trace had disappeared in the preserved specimens. 

 Verrucas present, arranged in forty-eight vertical rows, but smaller 

 and less distinct than in U. sulcata. There is also less modification 

 of the upper portion of the column, but there is a tendency to 

 form similar longitudinal furrows, although the body-wall retains 

 its firmness and is no thinner than the lower portion. Some 

 of the specimens still retained foreign particles adhering to the 

 verrucae (fig. 6). 



This species is somewhat taller and more slender than U. sulcata. 

 The largest individual measured 6 cm. in height and but 3*4 cm. in 

 breadth at its widest part (fig. 6). 



Tentacles. — Similar in arrangement and number to U. sulcata 

 (6 + 6 4- 12 + 24) (fig. 8). There is a slight tendency observable, 

 in some individuals only, to a longitudinal grooving, but in no case 

 have I observed that the mesoglcea participates. 



(Esophagus. — The cesophageal wall is much corrugated, and the 

 oesophagus extends into the coelenteron for a considerable distance. 

 Two well-marked siphonoglyphs are present. 



Ccelenteron and Mesenteries. — There are twenty-four pairs of 

 complete mesenteries, including two pairs of directives in relation 

 with the siphonoglyphs. All the mesenteries except the directives 

 are fertile. The longitudinal muscles are well developed and are 

 seen as distinct swellings on the faces of the mesenteries. Fig. 10 

 gives details of structure in transverse section, also showing structure 

 of ovary {ov.) and mesenterial filament {m.f.). The parieto-basilar 

 muscle (p.b.m.) is large and distinct. 



Sphincter. — The sphincter muscle is strongly circumscribed, 

 endodermal, and projects as a strong band into the coelenteron. 

 In transverse section (fig. 7) the main supporting mesogla?al trunk 

 is seen to break up into two secondary branches, a small one near 

 the base and a large one running the length of the muscle. From 

 each of these main trunks mesoglceal outgrowths radiate, supporting 

 the muscle fibres. 



Bodtf-iuall. — The body-wall is thick and firm to the touch. The 

 mesoglcea forms a stout supporting lamella (fig. 9), but the circular 



