54 JOURNAL OF THE [January, 



gives to a railroad embankment, or a levee is astonishing. In 

 this respect it is unequalled by any other grass." 



Mr. Hyatt stated that the condenser which he exhibited was 

 constructed by himself on the principle announced some time 



since by Prof. Alfred M. Mayer three plano-convex 



lenses, the largest one, of two inch focal distance, with a central 

 stop, placed below, and two smaller lenses, paired, with their 

 convex surfaces opposed to each other, and placed near the un- 

 der surface of the stage. The combination gives an excellent 

 dark ground illumination. 



A discussion was held upon the atmospheric discoloration of 

 the "Abbe glass." Specimens were exhibited, and were com- 

 mented upon by Mr. Wales. 



Meeting of October 17TH, 1890. 



The Vice-President, Mr. J. D. Hyatt, in the chair. 

 Twenty persons present. 



OBJECTS EXHIBITED. 



1. Spider crab, Liblnia caiialicidata, -zoea stage : by Ludwig 



RlEDERER. 



2. Mantis shrimp, Squilla euipiisa, alima stage : by Ludwig 



RlEDERER. 



3. Fore-tibia of the grasshopper, Scitdderia ciirvicauda Serv., 

 with auditory organ : by J. L. Zahriskie. 



4. Moult of fore-tibia of Orchellinum glaberrimum Burm., 

 with auditory organ : by J. L. Zabriskie. 



5. Malachite from Paterson, N. J.: by James Walker. 



6. Azurite from Paterson, N. J.: by James Walker. 



7. Fungus in solution of cocaine : by Frank D. Skeel. 



8. Sections of leaf of Long-leaved Pine of Colorado : by 

 P. H. Dudley. 



Dr. Dean remarked upon Mr. Riederer's exhibit of the alima 

 stage of Mantis as an especially interesting slide. 



A discussion upon the tenacity of life and the reproduction 

 of lost parts among the crustacese was participated in by Messrs. 

 Leggett, Dean, Lockwood and Helm. 



Mr. Zabriskie said that the green grasshoppers in general are 

 furnished with curious structures situated on either side of the 



