246 



Dr. J. A. Lamson was elected a Resident Member. 



The names of Professors W. B. and H. D. Rogers 

 were added to the list of Resident Members. 



DEPARTMENT OF MICROSCOPY. 



An extract from a letter of C. A. Spencer, of Canas- 

 tota, N. Y., to Dr. Dm-kee, was read to the Society. 



Mr. Spencer says that he is " manufacturing a new lens, which 

 he calls the ' Orthoscopic Eyepiece.' It is more perfectly achro- 

 matized than the old negative form, has a perfectly flat field, 

 and is more luminous. Its cost, he says, is high, (fifteen dollars ;) 

 still, he is satisfied it will meet a want long felt by microscopists." 



Alluding to some recent examinations of animal tissues with 

 his lenses, in connection with Mr. Clark, Prof. Agassiz's assistant, 

 Mr. Spencer says, ".one result of large angles of aperture in 

 such investigations was a gratifying and complete answer to the 

 objections made by some to such lenses. In studying tissues made 

 up of several laminae or layers, varying, perhaps, inter se, in their 

 textures, small angles of aperture give a confused mixture of all 

 the layei's at once, and the specific characters of none. We found 

 the large angles of aperture to insulate these beautifully and per- 

 fectly, — an effect of course valuable in the highest degree." 



Dr. John Bacon exhibited specimens of Foraminifera, 

 from South Carolina, and Polycistina from Barbadoes, 

 belonging to the Bailey collection. 



These fossils belong to the same group, and agree in some of 

 their essential characters. Tire calcareous carapaces of the for- 

 mer are perforated with numerous openings through which the 

 animal protrudes thread-like processes of its body for nourish- 

 ment. In the latter, the carapaces are siliceous, and, with the 

 exception of these, there are no organisms having siliceous 

 coverings, which have been positively determined to be animal. 

 They have been placed in the animal kingdom from their struc- 

 ture and the albuminous character of their substance, (sarcode,) 

 from their motion, and from the manner of obtaining nutriment, 

 distinct from that of vegetables. 



