256 



HARDWICKE'S SCIENCE-GOSSIP, 



MICROSCOPY. 



A Manual of the Infusoria. — By W. Saville 

 Xent, F.L.S, (London: David Bogue). Part v. of 

 this work has just been published. Only another part 

 remains to complete what all zoologists and micro- 

 scopists will agree in saying is perhaps the finest 

 work of its kind ever offered to the public. Mr. 

 Kent treats in detail of the different orders and 

 .genera, and describes all those species which are 

 figured. The life histories of many of the species are 

 carefully traced. The interesting genus Vorticella is 

 treated upon at great length. The eight plates which 

 accompany this part contain nearly three hundred 

 highly finished illustrations of different species of 

 Infusoria, in all the discovered stages of their 

 development. 



The Micrographic Dictionary. — Parts ii. and 

 iii. of the fourth edition of this invaluable work 

 Iiave just been issued. 



The "Journal de Micrographie." — This 

 excellent French microscopical journal now appears 

 .more regularly than heretofore. The parts for July 

 and August contain some capital articles on " Unicel- 

 lular Organisms," " Observations on Certain Species 

 ■of Saprolegniaceoe," &c. The " Revue " is a special 

 feature in this journal, and is written by the editor, 

 Dr. Pelletan. 



Bubbles in Glycerine Jelly. — These are pro- 

 bably due to the elasticity of the object which the 

 pressure upon the cover glass having been removed, has 

 gradually elevated it. The remedy is either to use a 

 cell or to use little or no pressure. If the jelly is kept 

 fluid for a short time the cover will sink down until 

 it touches the elevated part of the object ; the slide 

 iliould be placed in a moderately warm and dry place, 

 and kept there some time before cleaning off the 

 superfluous jelly. — F. K. 



How TO obtain Foraminifera from Chalk. — 

 I should be very much obliged for information as to 

 the best method of obtaining foraminifera and 

 •diatoms from chalk and clay and limestone. — Hickin. 



ZOOLOGY. 



Erosion of Shells. — Although much has been 

 written concerning the erosion of shells, I beg to offer 

 the following suggestion. It is well known that one 

 function of the epidermis is probably to protect the 

 limey portion of the shell from chemical action. 

 Now it appears to me that if the epidermis is 

 scratched or ruptured, by mechanical or other causes, 

 the calcareous layers of the shell would be laid bare 

 to the action of any acids occurring in the mud or 



water, just as in etching the acid only acts on the 

 copper where the wax has been removed by the 

 etching needle. I have before me some specimens 

 of Anodonta cygnea from a brook a few miles from 

 Godalming, which are so deeply eroded, that they 

 appear as if eaten into by a small slug or worm. 

 When first taken out of the water, many of the shells 

 had small dark hemispheres which appear to be 

 organic ; I do not know whether they are animal 

 or vegetable, but I believe they help to rupture the 

 epidermis. In some of my specimens the nacre is all 

 laid bare towards the hinges of the shell. Perhaps 

 it is only fair to add that I have seen old window- 

 glass eaten into in a similar manner. In this case a 

 small fungus I believe originates the point of attack. 

 I have remarked in the stagnant pools where small 

 shells are exceedingly abundant, dead, or bleached 

 shells are comparatively speaking of rare occurrence, 

 so I take it the shells are soon dissolved after the 

 death of the mollusca. — //. JV. A'idd, Godalming. 



Cormorants. — In reply to J. H. H.'s query at 

 page 210, I quote Thompson's " Natural History of 

 Ireland," vol. iii. page 240 : " In the middle of June 

 1833, some (cormorants) appeared about Lough 

 Neagh, in the vicinity of Ram's Island, and when 

 visiting the lake on another occasion, I was told that 

 a species of cormorant had bred on Scawdy Rock — a 

 low ridge — between Toome and Shane's Castle. 

 This is very improbable, and may have been 

 imagined from the circumstance of the birds being 

 seen there during summer." My own experience is 

 that there are several places in Lough Neagh — the 

 largest freshwater lake in the United Kingdom — 

 where numbers of cormorants are to be found "at 

 home " night and day, all the year round. There are 

 certain shallows where fish abound, and where the 

 stones are exposed in summer. There is a small 

 stony islet covered with brushwood, called Croghan, 

 three-quarters of a mile from the shore at my glebe, 

 where the fishermen tell me their nests have fre- 

 quently been found. The last I knew of was in 1876, 

 they may have bred since in the same place, as the 

 birds are as numerous as ever, but latterly the 

 operations of egg-stealers have all but obliterated the 

 nesting of the larger birds of our Lough. There is a 

 further reference in same vol. of Thompson to cor- 

 morants breeding in freshwater haunts, notwith- 

 standing the belief of the country people that " they 

 would die if they could not get a drink of salt water 

 within the twenty-four hours." At page 244, " Upon 

 an island in a freshwater lake at Castlemartyr, co 

 of Cork, the seat of the Earl of Shannon, the game- 

 keeper reckoned more than eighty nests of the 

 cormorant on Scotch fir-tree's not less than sixty feet 

 in height, about the year 1833." TJje authority for 

 this is given in a foot-note as " Proceedings of 

 Zoological Society of London, 1847," page 97.— 

 //. IV. Lett, M.A. 



