74 REPORT ON THK PENNATULIDA. 



touched or pulled they suddeuly drew themselves in with force, so as 

 nearly or quite to disappear. By this action the highly elastic axis 

 must be bent at the lower extremity, where it is naturally slightly 

 curved ; and I imagine it is by this elasticity alone that the zoophyte 

 is enabled to rise again through the mud." 



A little further on he says :— " It is always interesting to discover 

 the foundation of the strange tales of the old voyagers, and I have no 

 doubt but that the habits of the Virguhiria explain one such case. 

 Captain Lancaster, in his voyage in 1601, narrates that on the sea sands 

 of the island of Sombrero in the East Indies he found a small twig 

 growing up like a young tree, and on offering to pluck it up it shrinks 

 down to the ground, and sinks unless held very hard. On being plucked 

 up a great worm is found to be its root, and as the tree groweth in 

 greatness so doth the worm diminish ; and as soon as the worm is 

 entirely turned into a tree it rooteth in the earth, and so becomes 

 great. This transformation is one of the strangest wonders that I saw 

 in all my travels ; for if this tree is plucked up while young, and the 

 leaves and bark stripped off, it becomes a hard stone when dry, much 

 like white coral : thus is this worm twice transformed into different 

 natures. Of these we gathered and brought home many." 



These accounts are of great importance, as they prove beyond 

 all possibility of doubt that the erect position is the normal one for 

 Virgularia, and if so, it follows with almost absolute certainty that 

 the same must be the case with other allied and similarly constituted 

 genera. 



2. — Oil the Foicer of Retraction. — This, also, is a point of very consider- 

 able interest and importance. It will be noticed that both Darwin 

 himself and Captain Lancaster, in the accounts quoted above, state that 

 Virgularia has the power of retracting suddenly into the sand when 

 disturbed " so as nearly or quite to disappear." Humph says exactly 

 the same of V. juncea, which he describes as burying itself at low 

 water so far in the sand that only a bit of three or four fingers' 

 breadth projects. 



We do not yet know whether V. viirabilis also possesses this power 

 of retracting partially or completely into the mud when disturbed, but 

 from analogy it would appear by no means improbable that it does so. 

 The possession of this retractile power is clearly very advantageous for 

 the sake of protection, and it will be an interesting point for future 

 observation to determine whether this power is in any way a compen- 

 sation for the loss of the more usual means of defence — i.e., thread-cells. 

 We have but little evidence on this point as yet. Rumph distinctly 

 states that V. juncea does not sting, but does retract forcibly when 

 disturbed : while V. Ilnriqyhii, which possess very marked stinging 

 powers, is not mentioned as retracting. 



Supposing, which seems probable, that V. mirabili.i possesses this 

 power of retracting partially into the mud, it would help to explain 

 why the lower halves of the rachis escape, although the tops are so 

 constantly eaten off. 



