AMERICAN 
JOURNAL OF SCIENCE. 
JAMES D. ann E. S. DANA, anv B. SILLIMAN. 
ASSOCIATE EDITORS . 
Proressors ASA GRAY, JOSIAH P. COOKE, anv 
JOHN TROWBRIDGE, or Camsriner, 
Prorrssors H. A. NEWTON anp-A. E. VERRILL, or 
New Haven, 
Prorgssor GEORGE F. BARKER, or Patapecpata. 
THIRD SERIES, * 
VOL. XXVII.—[WHOLE NUMBER, OXXVII.] 
Nos. 157—162. 
JANUARY TO JUNE, 1884. 
WITH FIFTEEN PLATES. 
NEW HAVEN, CONN.: J. D. & E. 8. DANA. 
1884. 
