220 REPORT ON TUK PENNATULIDA. 



livint,' and dead polypes. The fact that the stems are frequently 

 dredged up of dead specimens, from which the whole of the animal 

 matter has been removed by decomposition, and which stems are very 

 slightly if at all more brittle than stems of living specimens, proves conclu- 

 sively that death of the polypes would not in any way cause or account 

 for truncation of the stem as well. We are therefore compelled to 

 reject this explanation altogether ; firstly, because it has not been 

 proved to be a true cause, for we have no evidence at all that the top 

 does actually die down as suggested ; and, secondly, even if a true 

 cause, it is an insufficient one, because it leaves completely unexplained 

 the truncation of the stem as well as of the soft parts. 



If the cause of the truncation then does not lie in the firinilaria 

 itself, it must be some force acting on it from without. Fish or other 

 marine animals knocking up against the colonies, and so breaking 

 them off, could not account either for the invariable occurrence of the 

 truncation or for its situation, for lateral blows would tend to cause 

 fracture not high up the rachis, but, as already explained, at the point 

 of emergence from the ground ; i.e.. Junction of rachis and stalk. 



The only other explanation that occurred to us, and the one we 

 advanced when presenting our report to the Birmingham Nataral 

 History Society on June 20th, is that the truncation is due to the tops 

 being habitually bitten or nibbled off as food by some marine animals, 

 most probably fish. At the time of presenting our report, this expla- 

 nation was offered as a pure hypothesis, in support of which we had 

 no direct evidence, and to which we were driven simply from inability 

 to conceive of any other that would satisfy the conditions of the 

 problem. Since this time we have been fortunate enough to obtain 

 direct evidence of a very striking and satisfactory nature in support 

 of our view. 



Mr. R. D. Darbishire, of Manchester, to whom we inentioned the 

 difficulty, told us he remembered many years ago taking specimens of 

 Vtrgidaiia from the stomach of a haddock caught off Scarborough. 

 Fortunately these specimens, which bear the date of the 9th November, 

 1855, were preserved, and Mr. Darbishire has very kindly handed them 

 over to us for examination. They consist of five fragments of 

 Virgularia mirabiUs, from three quarters of an inch to three inches in 

 length, each fragment containing the portion of stem belonging to it, 

 and all five showing evident signs of having undergone partial digestion. 



The most interesting point still remains to be noticed. Of these 

 five fragments no fewer than three are tops, i.e. actual perfect upper 

 ends, a point the significance of which is at once evident when we 

 remember that of the specimens of Virciularia mirahilis dredged either 

 off our own coast or elsewhere, only one single specimen — the one in 

 the Glasgow Museum — is known to have a perfect top. 



Mr. Darbishire's observation proves that fish do actually bite off 

 and swallow as food fragments of Virgularia ; also that they are able 

 to find specimens with perfect tops, for which tops they would appear 



