172 * Transactions. — Zoology. 



to Captain Hutton, who said it was an uudescribed species of 

 Opomyza . 



Some very interesting questions are presented for solu- 

 tion by this little creature : Has it any enemies in the hot 

 water where it develops ? If not, it is not surprising that 

 in its mature form it appears in such numbers all the year 

 round. Has it by long residence in the hot water changed 

 its nature, so that it no longer breeds at certain times of the 

 year ? Where food is abundant, and the temperature of the 

 water is practically the same the year through, there would 

 be no necessity for a breeding season. If the nature and 

 habits of the insect have been much changed from those of 

 its nearest relatives, these facts may indicate a longer period 

 of existence for our thermal springs than they are generally 

 credited with. 



The statement as to the gathering of the birds might also 

 be investigated. There is no natural bush of any extent 

 within miles of these springs, and the congregation at a par- 

 ticular time of the year of many native birds may be due to a 

 survival of an ancestral habit, as some avian migrations are 

 known to be. 



It is a curious thing that the cast-ofi shells should materi- 

 ally assist in building these natural incubators, as I am 

 certain they do. Complete sections of different basin-walls 

 should be made in order to ascertain if this process has been 

 in operation since the beginning of the terrace-formation. 



These questions are deserving of further study by a com- 

 petent scientist. 



Art. XX. — The Sipunculids of Netv Zealand. 



By W. B. Benham, D.Sc, M.A., F.Z.S., Cor. M.E.S. Tasm., 

 Professor of Biology, University of Otago. 



[Read before the Otago Institute, 3rd December, 1903.] 



Plato VII. 



Up to the present time only three species of sipunculids have 

 been recortled from our sliores, and these were described a 

 good many years ago, before it was customary to seek for 

 generic and specific characters in internal anatomical features ; 

 in other words, the external form, colour, and dimensions were 

 considered to vield sullicient material for diagnosis. It will 

 not be surprising, tlierefore. if a re-examination of these species 

 may necessitate their removal to genera other than those to 

 which they were originally assigned. 



