107 



Fig. 29. Cumulative curves of appearances of new species in successive samples from various 

 localities in the Gulf of California and northwestern Europe. 



A. Curves of 1/20 m- van Veen samples in two shallow environments in the southern Gulf 

 of California region. 



B. Curve of 9 successive samples from the northern shelf region, taken with a small shell 

 dredge, covering roughly 20 m^ per sample. 



C. Curve of mollusk species only from 5 equal-sized samples in one spot off Topalobompo, 

 Mexico, in a depth of 17 meters, using a 1/10 m^ Petersen Grab. 



D. Cumulative curves of species diversity in 20 consecutive stations each from a) Denmark 

 and b) England. 



cumulative curves for successive samples in boreal waters are reproduced 

 from Holme (1953) for Whitsand Bay, England, and from Petersen 

 and Boysen Jensen (1911) from Danish waters. There is no doubt con- 

 cerning the great diversity of Gulf of California waters as compared to 

 boreal waters when comparing this series of graphs. All of the Gulf of 

 California curves reach toward the asymptote, with little indication of 



