i8 



is moreover the position in which stalk and body lie in immature buds. C. dodecalopJuis has 

 six pairs of tentaculiferous arms, each of which ends in a swollen bulb containing remarkable 

 refrinofent vesicles. 



ö 



C. Icvinseni. (PI. I, figs. 5, 6. PI. III, figs. 23, 24). 



In their old condition, the zooids of this species are characterised by having an extremely 

 elongated, cylindrical form (PI. I, fig. 6; PI. II, fig. 11 ; PI. IV, fig. 33), the apparent length, 

 however, being commonly greater than the real length, in consequence of the fact that the 

 somewhat coiled distal end of the stalk, sometimes hearing a bud, together with several large 

 embryos, usually form a mass having the same diameter as the body, and so closely applied 

 to its posterior end that the limit between this mass and the body is not at once made out. 

 The eloneated masses seen in the cavities of the coenoecium in fio-. 1 1 thus consist, in most 

 cases, of zooid -f stalk + bud (if any) -y embryos. The extreme elongation of the old zooids is, 

 however, seen in the sagittal section shewn in fig. 33; from which it will be noticed that the 

 arms pack themselves away, during retraction, so as to form a continuation of the cylindrical 

 form of the rest of the zooid. 



In old individuals the stalk is always directed away from the mouth, and is usually 

 spirally coiled, the coiling being accompanied by some twisting round the longitudinal axis of 

 the stalk, as is indicated by the direction of the muscle-fibres (fig. 6) In younger blastozooids 

 (fig. 5), the proportions of the body tend to approach those of C. dodccalopJnis. Their stalk 

 originates relatively much nearer the oral end of the body, so that the bend of the alimentary 

 canal lies in a caecum of the body-wall which projects a considerable distance beyond the origin 

 of the stalk. As moreover the stalk is commonly carried in such a way that it lies asymmetrically 

 on one side of the body, pointing forwards, and with its di.stal end sometimes overlapped by 

 the proboscis, these young individuals have a resemblance to the adult C. dodecalophus which 

 is not shared by the adults of their own species. 



Buds are not produced in great profusion, although it may be suspected that in a more 

 actively growing colony, they would be more numerous. The old individuals, in which the 

 production of eggs is energetically taking place, usually have no buds at all. The specimen, 

 with young ovaries, shewn in fig. 6 has a single bud; and buds are certainly more numerous 

 in the two or three regions where the coenoecium has an immature character, at or near the 

 tips of its branches. These regions contain relatively young blastozooids, which have not yet 

 acquired the elongated cylindrical form of the adults. 



One of the most singular and characteristic features of C. levinscni is the form ot its 

 proboscis. This is not only relatively large, but it has an extraordinary amount of mobility, a 

 peculiarity correlated with the unusually long neck, or proboscis-stalk, of this species. It commonly 

 (during retraction) forms a sort of mantle, wrapping round a considerable part of the mass ot 

 arms and tentacles, as shewn in fig. 6. A glance at this figure wilI reveal the singular fact 

 that as compared with other species, the pigment-line is upside down; and fig. 11 also shews 

 various cases in which the position of the pigment-band is not what one would expect it to be. 



