Abstract
The relative abundances of Species of crustose coralline, as derived from areal measurements of large collections taken fromNova Scotia to Labrador, are given as a function of depth and as a function of mean maximum temperature and depth. The relative effects of depth and temperature independently are indicated and in most cases the results are markedly similar to those found in earlier Gulf of Maine studies. The distributions of Pseudo-lithophyllum orbiculatum and Phymatolithon rugulosum apparently are not controlled by summer temperatures in this area.