g/So_188, Vou XXVIN DECEMBER, 1884, _ 
Established by BENJAMIN SILLIMAN in 1818. 
THE 
AMERICAN 
JOURNAL OF SCIENCE. | - 
EDITORS . ae 
JAMES D. ayy E. S. DANA, anv B. ae 
ASSOCIATE EDITO 
Proressofs ASA GRAY, pan P. COOKE, AND 
JOHN TROWBRIDGE, OF Camnriper, a 
Proressors H. A. NEWTON anp A. E VERRILL, OF 
New Haven, ae = 
Proresson GEORGE F. BARKER, ‘OF Panapenem 
THIRD SERIES. 3 Z 
VOL. XXVIIL —[WHOLE NUMBER, oxxvit. i: 
No. -168—DECEMBER, 1884. 
NEW HAVEN, CONN.: J. D. & E, 8. Di 
