Acantharia in the Atlantic Ocean, Their Abundance and Preservation1

In plankton samples from the Atlantic Ocean preserved in buffered seawater‐form‐aldehyde, it has been unusual for the spicules of Acantharia to be so seriously eroded as to interfere with their taxonomic study; some families are more susceptible to erosion than others. Acantharia are never rare in samples from reasonably deep oceans; in No. 10‐mesh net collections they almost always make up more than 1%, very often 10–20%, and frequently over 30% of the organisms caught. Available data show Acantharia generally more abundant than Foraminifera or Radiolaria, although these three groups of Sarcodina show covariance in abundance.