1893.] NEW-YORK MICROSCOPICAL SOCIETY. 121 



2. " Scarf " of Anaconda. 



3. Skin of the Lizard, A noils principalis, under a \ objective, 

 showing "the windows." 



4. Skin of the Horned Toad, Phrynosoma cornuta, under a \ 

 objective, showing pigment grains. 



Exhibits Nos. 1-4, inclusive, were by Samuel Lockwood. 



5. Photomicrograph, half-tone print, of scale of Podura, 

 Lepidocyrtis curvicollis, x 3,000 : by H. G. Piffard. 



6. Photomicrograph of pygidium of Flea, taken by Dr. Henri 

 Van Heurck, who regards this object as a test, second in value 

 only to the Podura scale : by H. G. Piffard. 



7. Various Diatoms : by Noah Palmer. 



Some points on the changeability in color of the skin of the 

 Chameleon, in Dr. Lockwood's address, were discussed by 

 Messrs. J. D. Hyatt, L. Riederer, and W. J. Lloyd. Mr. 

 Riederer suggested that the changeableness may be somewhat 

 on the principle of " Newton's rings," since there are two films 

 in the skin of the chameleon. 



Meeting of June 2D, 1893. 



The President, Mr. Charles S. Shultz, in the chair. 



Twenty-four persons present. 



Dr. H. G. Piffard read a paper entitled *' An Improvement 

 in the Correction of Lenses for Photomicrography, Photogra- 

 phy, and Photoastronomics." This paper was illustrated by 

 many photomicrographs, as cited below. 



OBJECTS EXHIBITED. 



1. Watson's Van Heurck Stand : by H. G. Piffard. 



2. Navicula rhomboides, under a William Wales -^^, made 

 eighteen years ago : by H. G. Piffard. 



3. The same ; resolution of " beads," with parabola : by H. 

 G. Piffard. 



4. Podura scale : by H. G. Piffard. 



5. Photomicrographs : blood of Amphiutna, Echinus spine, 

 probe platte, histological section, Podura scale, Amphipleura 



pellucida, Limulus, copy of a painting, street scene, interior 

 view : by H. G. Piffard. 



