428 MR, A. MtJLLEE ON A CHINESE ARTICHOKE GALL. 



and we ourselves sliould be rather sanguine that by introducing 

 tlio common pearls within the valves of the true pearl-mussel we 

 should obtain good pearls. Lastly, is it possible to improve the 

 mean-looking pearls produced in such quantities in some localities 

 in the edible mussel ? "We have made a few experiments in this 

 last direction ; and though we have not made our fortune or taken 

 out a patent, we have found that they really may be much im- 

 proved by chemical means, some made quite ornamental. The 

 method we have tried is boiling the pearls for a short time in a 

 dilute solution of potash and afterwards letting them remain in it 

 for a few days, noting that a very strong solution destroys their 

 lustre instead of increasing it. These inferior pearls have been col- 

 lected for sale for many years in the lower Conway ; and we think 

 it possible that they are afterwards submitted to some such pro- 

 cess. The pearls which are obtained from the Alasmodon, between 

 Llanrwst and Bettws-y-coed, are very different and need no such 

 treatment ; in fact some of those found have fetched a high price, 

 and they appear to wear better than oriental pearls. 



Late in August of this year I examined a dozen Alasmodons ; 

 none of them had the ova transposed to the branchiae, though they 

 were ejecting them from the oviducts. The pericardium could be 

 made out to communicate with the suprarenal sacs, as Professor 

 Bolleston, I think, was the first to ascertain. In the depth of the 

 foot of the Anodon, at some distance before and below the pedal 

 ganglion, is a little yellowish-brown body about the size of a mus- 

 tard-seed, of a waxy consistence and formed of several eniboUures, 

 "We should consider this to be a rudiment of a byssus-gland rather 

 than of the organ of hearing. There is also a curved band of yel- 

 lowish thickened mantlebelow the hinge, whichrequires explanation. 



Note on a Chinese Artichoke Grail (mentioned and figured in Dr. 

 Hance's paper " On Silkworm-Oaks ") allied to the European 

 Artichoke Gall of Aphilothrix gemmce, Linn. By Albert 

 MtJLLER, F.L.S. 



[Bead February 15, 1872.] 



From the valuable " Supplementary Note on Chinese Silkworm- 

 Oaks," by Dr. H. F. Hance (Journ. Linn. Soc. Botany, vol. xiii. 

 No. G5) I select for consideration the following passages, which 

 are of special interest as affording the first intimation of the oc- 

 currence of a cynipideous oak-gall new to science : — 



