MICROSCOPICAL MEMORANDA. 127 



sessed considerable extensile and retractile powers, and the whole pre- 

 sented much the appearance of a cluster of the tentaculse of a polyp. 

 The author described minutely the internal organization, mode of pro- 

 gression, and other peculiarities of the animal, and strongly recom- 

 mended the members of the Society to make search for additional spe- 

 cimens, assuring them that they would be amply repaid by an inspec- 

 tion of this very curious and interesting creature. 



Mr. Calwell exhibited a specimen of the animal described by Mr. 

 Bergin, prepared in balsam : he stated, that he had more than once met 

 with it, but was unacquainted with its name and history. 



Dr. Hill mentioned, that a few days since, a specimen of the same 

 animal had been given him, which was obtained from a pond in the 

 county of Meath ; and that, being unacquainted with it, he had for- 

 warded it to Mr. Bergin, who happened to be engaged at the very time 

 in inquiries relative to the same creature. 



Dr. Hill then read a brief notice of some peculiar appearances exhi- 

 bited at this season of the year by diseased wheat, when examined 

 under the microscope. 



Micrometers. For the sake of those of our readers interested in the 

 use of these instruments, we find in the Bulletin de la Societe Imperiale 

 des Naturalistes de Moscou, No. 3, Annfo 1837, a paper by Professor 

 Alexandre Fischer, " On the advantages of Micrometers in the Focus 

 of the Eye Piece of Compound Microscopes, and on the mode of placing 

 them ;" but as our space does not allow us to enter into the details and 

 formulae, which occupy twenty-six pages, we must rest satisfied with 

 referring only to the above quotation. 



On Microscopic Vegetable Skeletons found in Peat, near Gainsborough, 

 by Mr. Binney, of Manchester. Mr. Bowman read a paper at the last 

 meeting of the British Association on some skeletons of fossil vege- 

 tables, found by Mr. Binney, in the shape of a white impalpable powder, 

 under a peat-bog near Gainsborough, occupying a stratum of four to 

 six inches in thickness, and covering an area of several acres. It re- 

 mained unchanged by sulphuric, hydrochloric, and nitric acids, and by 

 heat, and was concluded to be pure silica, in a state of extremely 

 minute subdivision. On submitting it to the highest power of the 

 compound microscope, it was found to consist of a mass of transparent 

 squares and parallelograms, of different relative proportions, whose 

 edges were perfectly sharp and smooth, and the areas often traced with 

 very delicate parallel lines. On comparing these with the forms of 

 some existing Conferva of the tribe Diatomacete, which are parasitical 

 on other Algce both marine and fresh water, but so minute as to be 

 individually invisible to the naked eye, the resemblance was found to be 

 so strong as to leave no doubt of their close alliance, if not perfect 

 identity. Mr. Bowman considers them to be the counterparts of the 



