53 



Leucodore ciliatus — Prof, T. H. Huxley, The English Illustrated 

 Magazine, No. 1, Oct. 1883, pp. 46 to 55 ; 

 No. 2, Nov. 1883, pp. 112 to 121. 

 „ ,, Dr. W. A. Haswell, Centennial Magazine, 



Sept. 1889, p. 148. 

 Polydora (Leucodore ) ciliata (Johnston) — Alexr. Agassiz, Annals 

 and Magazine of Natural History, vol. xix, ser. 3, 1867, p, 

 242, pis. V. and vi. 

 Pohjdora (Leucodore) ciliata — Dr. W. A. Haswell, Proceedings 

 of the Linn^ean Society of New South Wales, vol. x, p. 273. 



There are very many other papers bearing on the habits of the 

 worm, amongst which may be mentioned one Vjy Dr. Wright in 

 the Edinburgh New Philosophical Journal, 1857, vol vi, p. 90 ; 

 another by Mr. Alexander Oliver in the Centennial Magazine for 

 September, 1889, pp. 134 to 148 ; and some details of the habits 

 of the worm are given by Sir J. Dalyell in his work on the Powers 

 of the Creator Displayed in Creation, 1851, vol. ii, p. 159. 



SUPPLEMENTARY NOTE. 



SiNCK the foregoing was written, I have received a number of 

 oy.sters tlirough ti)e Department of Fisheries, from the Clarence 

 lliver, which had been in fresh-water for 13 days, owing to the 

 flood waters spreading over the l)eds. An examination of these 

 oysters tends to conMrm the opinion already expressed in the 

 body of this report. 



Out of 200 oysters, 50 were found to have been attacked by 

 the worm, and 25 of these exhibited the early stages of the 

 disease. Tiie area occupied by the worms was of variable extent, 

 but mostly small ; the patches of mud being covered by deposits 

 formed by the oysters ; 15 out of the 25 specimens were in the 

 membranous stage, and in the rest the deposits were partially 

 calcified. In the whole of the 50 specimens the position occupied 

 by the worms was on the anterior margin of the shell, about mid- 

 way between the hinge and tlie ventral edge. On clearing away 

 the patches of mud, which were covered with membrane only, the 

 surface on which the body of the worm rested was found to be 

 perfectly smooth, and without any trace of erosion; whilst in 

 those in which the deposited layers were thick and fully calcilicd, 

 slight traces of grooves were visible near the margin. In every 



