SCIENCE-GOSSIP. 



297 



on Afton Down, also var. infiata ; var. bizona, a 

 numerous colony on High Down, near Fresh- 

 water, C. A. 



Bulimus obscunis. — Frequent under stones, G. G. 

 Boniface Down and Steephill Cove, C. A. 



Pupa umbilicata.Steepb.\\\, A. J. H. Very com- 

 mon under stones about Ventnor, G. G. St. Helen's 

 Spit, often found in the empty shells of H. 

 nemoralis that have been broken by thrushes, 

 A. G. M. Hempstead Hill, C. A. Norton, near 

 Yarmouth, J. H. A. 



Pupa marginata. — Bembridge Down, Miss F. M. 

 More. Steephill, A. J. H. Common about Ventnor, 

 but less so than the last species ; a toothless variety 

 occurs, G. G. Ventnor and Steephill, C. A. 

 Norton, near Yarmouth, C. A. 



Pupa secale. — Qn. limestone rocks; local, but not 

 scarce; Steephill, A. J. H. Near the parsonage, 

 Ventnor, G. G. South face of Boniface Down, 

 abundant, C. A. Chalkpits, Afton Down and 

 Freshwater Down, C. A. Norton, on the blocks 

 of Bembridge limestone, J. H. A. 



Vertigo edentula. — A young specimen, named by 

 Mr. Alder, has been taken by Rev. W. E. 

 Hambrough at Alverstone, and another in Steep- 

 hill quarry. 



Vertigo minutissima. — Under stones on the shore, 

 St. Laurence, A. J. H. Steephill (two), C. A., 1S66. 



Vertigo pygmaea. — Copse between Ventnor and 

 Steephill, Sir W. Jardine. In moss, etc., Steep- 

 hill Cove, A. J. H. and C. A. Hempstead Hill, 

 under old bricks, C. A. 



Vertigo antivertigo. — Upon stones and aquatic 

 plants in marshy places ; Steephill and near 

 Woolverton, A. J. H. Colwell Bay, Mr. Alder. 



Balea fragilis. — Trunks of trees in woods, Steep- 

 hill and St. Laurence, A. J. H. Quarr Copse and 



Centurion's Copse, A. G. M. Copse near Yarmouth, 

 under felled timber. 



Clausilia lamhiata. — In moss about trees, etc., 

 A. J. H. Near Bembridge, A. G. M. Shanklin 

 Copse and Pelham Wood, G. G. Hedge on down 

 above Ventnor, C. A. 



Clausilia rugosa.— Common in moss and under 

 stones, G. G. St. Laurence, C. A. Copse near 

 Yarmouth, C. A. 



Cochlicopa lubrica. — Frequent in moss and beneath 

 stones ; Centurion's Copse and St. Helen's Spit, 

 A. G. M. Steephill, A. J. H. and C. A. The 

 Undercliff generally, G. G. Copse near Yar- 

 mouth, C. A. 



Carychium minimum. — Frequent in damp moss, 

 etc., Steephill, A. J. H. Marshcombe Copse, 

 Yaverland and Centurion's Copse, Bembridge, 

 A. G. M. Shanklin Copse and mossy stones near 

 a stream, Woolverton, G. G. Hempstead Hill, in 

 damp places, C. A. 



Achatina acicuia. — Above chalk-pit on Afton Down 

 (two), C. A., July, 1S79. 



Cyelostoma elegans. — Under stones in damp fields, 

 etc., Steephill, A. J. H. Common near Bembridge, 

 and especially abundant on the chalk, A. G. M. 

 Pelham Wood, the landslip, etc., G. G. Ventnor 

 C. A. Thorley and Norton (near Yarmouth), 

 around stumps of old trees, C. A. 



Sub-fossil. — In a cut path, Orchard Bay, I 

 observed a layer of shells, chiefly Cyelostoma 

 elegans, Helix aspersa, H. nemoralis, H. virgata, 

 H. caperata, about twenty inches below surface 

 of the soil. 



Fossil. — Suceinea oblonga rather numerous, and 

 many others in superficial beds at Totland Bay and 

 Freshwater, vide Forbes, in Mem. Geol. Survey, 

 pp. 5 and 8. 



MICROSCOPIC SLIDE CEMENTS AND VARNISHES. 

 By Charles F. Rousselet, F.R.M.S. 



TN the February number of Science-Gossip, 

 Dr. P. Q. Keegan recommends (ante p. 286) 

 a new micro cement-varnish, made of Canada 

 balsam and Styrax balsam dissolved in benzol and 

 shellac dissolved in alcohol. I am quite un- 

 acquainted with this cement, but should like to 

 make some theoretical remarks on that as well as 

 on some other micro- cements. The first result of 

 mixing the above substances will be, as Dr. Keegan 

 says, to precipitate the shellac as a fine powder, 

 which will then collect in a layer at the bottom of 

 the bottle. On shaking it up, the shellac will be 

 suspended in the solution in isolated solid particles, 

 but will never eftect a union with the other sub- 

 stances, and its only result will be a thickening of 

 the balsam solution. The addition of shellac will 



in no way modify the Canada balsam, which, when 

 exposed to the air, undergoes a double change with 

 age. First the solvent (benzol in this case) 

 evaporates, then some substances contained in the 

 balsam oxidize, and it is gradually converted into 

 a dry powdery resin. This cement may be good 

 and useful for some purposes, but I cannot see how 

 a Canada balsam slide can be protected for long 

 by a cement consisting mainly of the same sub- 

 stance and liable to disintegration. 



The office of a good cement- varnish is to 

 permanently prevent the escape of the mounting 

 fluid and to protect it absolutely from evapora- 

 tion. The correct principle, in my opinion, is 

 to choose a cement, irrespective of its brittleness, 

 which will not affect, nor be affected by, the 



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