98 



within the surf zone, Heterodonax was exceedingly abundant in certain 

 localities and large handfuls could be taken easily at the water's edge. 

 Various species of Donax were abundant as dead shell, but very few living 

 specimens were observed at any time. Great numbers of Tiirritella shells 

 were observed in freshly-deposited strand lines along the shore, but none 

 were collected alive, not even by means of grab samples taken fairly close 

 to shore. Emerson and Stillman Berry (personal communication) 

 reported abundant living populations of Turritella just outside the surf 

 zone in the Puerto Penasco and Guaymas regions. Buchanan (1958) found 

 Turritella in large numbers at the shelf edge, while Turritella is found at 

 intermediate shelf depths in European boreal waters (Thorson, 1957). 

 The most abundant living gastropods were the Olivellas, Olivas and 

 Terebras. 



Eight bottom grab samples were taken in depths of 5 to 11 meters on 

 sand bottom, using a small 1/20 square meter Van Veen grab. The living 

 mollusks found in these stations (shown below) give an idea of the relative 

 abundance and diversity of animals which can be found in small samples 

 from this environment. 



Total 6 



