56 REPORT ON THE PENNATULIDA. 



{videVl. I., Fig. 2, and PI. TIL, Fig. 8). In Funicidina the stem extends 

 the whole length of the colony, while in Pennatula the stem reaches the 

 bottom of the stalk, but stops short some distance from the top of the 

 rachis. In Pennatula it is also bent back on itself at both ends in the 

 form of a hook. 



In Virgularia the stem (Fig. 2) extends the whole length of the 

 colony. In the stalk, according to Dalyell, Kolliker, and Koren and 

 Danielssen, the stem tapers gradually downwards, ending in a fine 

 flexible point, which reaches to the bottom of the bulbous termination 

 of the stalk, and then turns back on itself for a short distance, ending 

 in a small hook, much as in Pennatula. In the rachis, starting 

 from below at its junction with the stalk, the stem at first enlarges 

 slightly, attaining its maximum diameter at about the point marked c in 

 Fig. 2 ; above this point it diminishes in size, but very gradually, 

 remaining of considerable thicknsss throughout the length of the 

 rachis, and ending at its top in an abruptly truncated extremity. 



In the Oban speciinens the diameter of the stem at its widest part 

 varies from 0-026in. to 0-050in. ; at its upper end, which, it must be 

 remembered, is imperfect in all the specimens, from 0-OlGin. to 0-039in. 

 The average taper from the widest part of the stem upwards is •002in. 

 per inch length of stem. 



In the Glasgow specimen of Virriuhiria ntirahiUf;, in which the top is 

 perfect, the upper end of the stem projects above the top of the fleshy 

 rachis for a length aboiit equal to its own diameter ; and a similar 

 condition has been noticed by Herklots, Koren and Danielssen, and 

 others, in perfect specimens of allied species of Viryularia. The most 

 obvious explanation of this feature is that the fleshy coenosarc has, 

 owing to the action of the spirit in which the specimens are preserved, 

 contracted slightly and so left the end of the stem bare ; but there 

 appears to be some doubt as to whether this is the true one. Koren 

 and Danielssen speak on this point as follows : — " Herklots and several 

 others have x^resumed that the reason of the axis being bare at the 

 upper end is to be sought for in a contraction of the sarcosoma under 

 the influence of the preserving liquid : this is, however, not the case ; 

 on the contrary, we are convinced that it is a natural state, and not 

 produced by any contraction of the coenosarc. As well in this species 

 [Virgularia affinis) as in many other genera and species, all the speci- 

 mens exhibited during life the same bare axis, and likewise the 

 sarcosoma connate with (attached by growth to) the axis at the place 

 where the axis begins to be bare. In one specimen we even saw 

 several serpuhe attached to the bare part." * This last statement is 

 certainly strong evidence in favour of the view advocated by the 

 Swedish naturalists, for the specimen in question was brought up 

 living, and the serpulce could not have attached themselves to the 

 stem unless it had been already bare while in the water. 



* Sars, Koren and Danielssen: " Fauna Littoralis Norvegise," Part 3, J877, 

 p. 91, note. 



