REPORTS ON THE COLLECTIONS OBTAINED BY ALLAN HANCOCK PACIFIC EXPEDITIONS OF 

 VELERO III OFF THE COAST OF MEXICO, CENTRAL AMERICA, SOUTH AMERICA, AND GALA- 

 PAGOS ISLANDS IN 1932, IN 1933, IN 1934, IN 1935, in 1936, IN 1937, AND IN 1938. 



A REMARKABLE NEW GENUS OF 

 SEA-URCHIN (Spatangidae) 



(Plate 17) 



By HUBERT LYMAN CLARK 



