Botany and Zoology. 237 



This face is seen only on one side of ^Pj, . The angles of the 

 dome and unit pyramid agree within one or two minutes with 

 those tabulated in Dana's System. 



Like the Kaiserstuhl variety the crystals are strongly pleo- 

 chroic ; almost colorless parallel with the £-axis, deep yellow par- 

 allel with the a-axis, less intense yellow parallel with the c-axis. 

 The crystals are abundantly filled with inclusions of irregular 

 form arranged zonally parallel with the prism faces, making an 

 analysis impracticable. They are doubtless mere dirt or debris 

 brought in by the original barium-bearing solution. 



16. On the serpentine of Montville, N. J. ; by George P. 

 Merrill. — A paper recently published in the Proceedings of the 

 U. S. National Museum (pp. 105-111, 1888) gives an interesting 

 description of the New Jersey serpentine, tracing its alteration 

 from the original diopside which is observed in many cases as 

 a nodular nucleus. The following analyses give for one case, the 

 composition of the pyroxene and the resulting serpentine. 



Si0 2 MgO CaO A1 2 3 Fe 2 3 FeO Ign. 



Pyroxene 51-45 18-43 24'02 2-94 1-06 0-96 1-08 = 99-94 



Serpentine 40-23 39-46 2-18 4-02 tr. 14-24=100-13 



17. Slipping planes and lamellar twinning in Galena; by W. 

 Cross. — It is shown that the cleavage masses of galena from 

 Bellevue, Idaho, are remarkable for the exhibition of lamellar 

 twinning clue to pressure. Two kinds of structure are described ; 

 in one, bands are seen on a cleavage surface that are parallel to a 

 dedecahedral plane ; in another, the laminae are parallel to dif- 

 ferent planes but all conform to a common law, the twinning- 

 plane being the octahedron 3. — Proc. Colorado Sci. Soc, vol. ii, 

 part 3. 



18. Some New York Minerals and their localities / by Frank 

 L. Nason. — An account is given of fine crystals of brown tour- 

 maline from Newcomb, Essex Co. ; pyroxene and associated min- 

 erals f rom Ticonderoga, and calcites from Rossie, the last collected 

 by Professor Emmons. — Bull. N. Y. State Museum, No. 4. 



III. Botany and Zoology. 



1. Certain relations of the cell-wall. — Dr. Kohl (Bot. Centralbl. 

 xxxvii, 1) demonstrates that the growth in thickness of the hairs 

 of many plants is not strictly by intussception nor by apposition, 

 but by periodic depositions of layers of cellulose ; and he notes 

 the fact that, between these successive layers, there is generally 

 a trace of protoplasmic matter not easily detected by the use of 

 Millon's reagent. Krabbe has already shown that the growth of 

 bast-fibres is substantially of the same character. g. l. g. 



2. The chemical nature of assimilation. — Th. Bokorny (Er- 

 langen, 1888) has conducted some interesting experiments de- 

 signed to test the truth of the hypothesis of Baeyer, namely, that 

 when sunlight acts on chlorophyll which is surrounded by car- 

 bon-dioxide the gas undergoes dissociation as if it were exposed to 



