REPORT ON THE PENNATULIDA. 



and becomes cylindrical. At about six inches from the top (Fig. 3), 

 at which point it attains its greatest size, the diameters are — lateral, 

 0"22iu. ; dorso-ventral, 0-20iu. ; above this point it tapers rapidly to the 

 top. 



We have been unable to examine the internal structure of the 

 stalk and rachis, as the specimens were destined for museum purposes. 

 Kolliker* has shown, however, that they are travei-sed along their whole 

 length by four main longitudinal canals (Fig. 3, ti), one dorsal, one 

 ventral, and two lateral, from which smaller canals arise forming a 

 rich network of nutrient vessels traversing the coenenchym, and com- 

 municating, as we shall see shortly, with the body-cavities of the 

 polypes. We have been able to confirm the existence of these main 

 canals, though we have not had an opportunity of tracing them along 

 their whole length. The smaller canals, with their openings into the 

 cavities of the polypes are shown in Plate II., Figs. 10 and 15, i\ 



The integument of both stalk and rachis is, according to Kolliker, 

 thick, and closely studded with minute fusiform calcareous spicules. t 



In stating that the stalk is, in the natural condition, inserted in 

 the mud of the sea bottom, we rely mainly on the very definite state- 

 ment of Forbes, who says :* " It lives erect, its lower extremity, as it 

 were, rooted in slimy nmd.'" Additional evidence on the point is 

 yielded by the anatomical ai-raugement of the parts, especially of the 

 stem (as will be noticed immediately) ; and by the fact that the allied 

 genus Virgularia is known to live erect. § Sir AVyville Thomson'! 

 also speaks of " passing over a forest" of Funiculina. clearly implying 

 that they live erect. 



2.— The Stem.— 



The stem (Fig. 2) extends from the top of the rachis to within a 

 short distance of the lower end of the stalk. As shown in Fig. 3 c, it 

 is quadrangular in section, but the sides are not perfectly flat. The 

 dorsal surface is slightly convex (flat in some specimens) along the 

 greater part of its length, but becomes concave in the stalk : the ventral 

 surface is slightly concave ; while the lateral surfaces, which are 

 rather narrower than the dorsal and ventral ones, are decidedly concave. 



The stem is thickest at the junction of the rachis and stalk, 

 where its transverse diameter is O'lO in., its dorso-ventral diameter 0'08 in. 

 From this point it tapers towards the upper end, at first very gradually, 

 then more rapidly ; its upper part being very slender and flexible : 

 towards the lower end it tapers gradually for a short distance, and 

 then rapidly, ending in a fine flexible and imperfectly calcified point 

 which enters the bent portion of the stalk, and ends a very short 

 distance from its extremitv. 



* Op. cit.. pp. 253-254. + Op. cit., p. 253, and Plate XVIII., Fig. 154. 

 i "Johnston's British Zoophytes." 2nd edition, 1847, Vol. i., p. 1G5. Cf. als( 

 Richiardi, " Monografia della Famiglia dei Pennatularii," p. 91. 

 § Darwin, " Naturalist's Voyage Kound the World," 1860, p. 99, 

 il Thomson, " Depths of the Sea," 1873, p. 149, 



