the Trondhjem Fiord. 449 



2 rnillirn. in diameter at the base, and thence tapirs gently to 

 the summit, where it is half that diameter. When living 

 the stem is cylindrical and vertical, so that the crown of 

 branches is held at its height above the mud ; but when dead 

 all efforts to preserve it in its natural form failed and the sides 

 entirely collapsed, and it is thus evident that the stem is com- 

 posed of a very delicate smooth surrounding membrane, filled 

 with fluid ; the fluid must escape, I think, at the top of the 

 stem between the bases of the branches, as I cannot find any 

 rupture in the side-walls. Delicate as the membrane which 

 forms the stem is, it is of considerable strength ; the stem 

 may be bent in any number of folds, it will not break. At 

 the summit of the stem this membrane expands and invests 

 the base of the crown, extending a little distance up the 

 branches, on tlie sides of which it is extended as a thin film. 

 The crown is about | inch high, and is composed of dicho- 

 tomously dividing flexible branches. 



The zooecia viewed from above (PI. XIX. fig. 3) have the 

 lateral margin straight, without any sinus, and the terminal 

 spine-point is small and does not rise above the slightly pro- 

 jected anterior margin of the zooecium ; viewed laterally (fig. 4) 

 the dorsal margin is seen to be straight or only very sliglitly 

 arcuate. The avicularia (fig. o) are greatly elongated and 

 at the base the point of attachment is extremely fine ; they 

 spring from the delicate lateral margin of the zooecium about 

 or a little above the middle, and are so long that they project 

 when directed forwards considerably beyond the summit of 

 the zooecium, sometimes by the whole length of the mandible. 



B. Kinekoskias cyathus (Wyville-Thomson). (PI. XIX. 

 figs. 6-8.) 



1877. Naresia cyaihus, Voyage of the 'Challenger,' The Atlantic, 



p. 142, and woodcut. 

 1881. Buyula (A7«fto*A:j;««)cya</tMS, Busk, Quart. J ourn. Micr. Sci. n. s. 



vol. xxi. p. 1, pi. i. figs. 1, -3, 4. 

 1884. KinehoHkias cyathus, Busk, lieport 'Challenger' Polyzoa, The 



Cheilostomata, p. 44, pi. viii. figs. 1 and 1 a-c. 



Judging from the figures given, as well as from the frag- 

 ment which I have liad the opportunity of examining, this 

 species is much less flexible and more charged with calcareous 

 matter than the last. Hence its crown, which is also con- 

 siderably larger than that of K. Smitti in relation to the 

 height of the stem, stands up more stiffly. But be that as it 

 may, the following points afford good specific characters. 



The zooecium seen from above (PI. XIX. fig. G) has the outer 

 margin flexuous ; at a short distance from the base it suddenly 



Ann. & Mag. N. Ilist. Ser. 6. Vol. xii. 34 



