ADAMS: VALLONIA COSTATA + EXCENTRICA. 365 



V. exce7itrica 81-84 transverse rows of 29 teeth. Presumably, we 

 may take it for granted that a sufficiently long series of radulcC have 

 been found to be constant, and that there are no intermediate forms. 

 It may be as well to defer giving a special name to V. costata of the 

 eccentric form until the radula has been examined, and it would also 

 be interesting to note whether symmetrical and eccentric individuals 

 interbreed. 



On the Danger of using Mercuric Chloride in the Sterilization of 

 Highly-Polished Shells.— Sometime back, after reading Mr. Byne's paper in 

 \\\\% Journal {vo\. 9, p. 172, 1899), I thought it advisable to sterilize my shells, and 

 started, unfortunately, on some of my best, viz., Cypraa pallida (Gray) ; these 

 shells of the dark type had a brilliant polish and free from any markings or spots 

 other than the natural ones on the shells. I soaked them for two days in warm 

 water at about 37°C., then put them in a solution of mercuric chloride, i gramme 

 in 500CC. of water. They remained in this for twenty-four hours at 37°C. , were 

 then taken out and allowed to dry without polishing. I made sure that the 

 HgCla solution was not acid, yet when I started to polish up the shells with a 

 clean duster I found that the lustre was considerably impaired, and that the shells 

 were marked nearly all over with bright yellow metallic looking spots that seem 

 to have got underneath the enamel of the shell, and through microscopic cracks 

 in the enamel ; there being no chance of reducing mercuric chloride to metallic 

 mercury, in the present case the only thing I can suggest is the formation of a thin 

 film of mercuric sulphide through decomposition of traces of organic substance in 

 the shell itself, containing a sulphur compound. — B. R. Lucas {Read before the 

 Society, January loth, 1906). 



Testacella haliotidea at Godalming. — Last evening I captured five specimens 

 of Testacella haliotidea upon a stone wall bounding the garden of one of my 

 colleagues here. The slugs were apparently crawling down the wall from the ivy 

 which climbs thickly over the top. They were about five feet above the ground. I 

 imagine that the recent heavy rains had driven them out of the ground, and that 

 they had taken refuge in the ivy, and on the return of hot dry weather were making 

 for their usual subterranean quarters. I have never heard of this slug being taken 

 here before, though I have lived here for over fifteen years and have always kept a 

 look out for it for the sake of our museum collections. — Oswald H. Latter {Read 

 before the Society, June 13th, 1906). 



Numerous Species in a Restricted Area. — In a small wood at Georgenthal, 

 Thuringia, about fifty yards square, I found in May, 1904, the following species: — 

 Helix pomatia, H. neinoralis and varr. poirctia ?iXi<\ giiielinia, H. hortensis a.nd varr. 

 qiiinque-vittata, liitea, baudonia, hoiichardia, H. strigella, II. frtuicum, H. incar- 

 iiata, H. lapicida, H. itala, H. obvoliita, H. persouata, H. hispida and varr. 

 concinna and albida, H. arbustorum var. canigoneiisis, H. rotundata and var. 

 alba, Bulimimis ntonfanus, B. obsciirtts, Claiisilia biplicata, CI. laniinata, CI. 

 plicatula, Azeca tridens, Cochlicopa lubrica, Vitrina pelliicida, Hyalina helvetica, 

 Hy. nitidtda, Hy. crystallina, Hy. cellaria. — F. H. SiKES {Read before the Society, 

 March 14th, 1906). 



