218 University of California Publications in Zoology — [Vou. 14 
It will be seen that the gastropods comprise approximately 50 
per cent of the outside fauna. This proportion is greater by 12 per 
cent than obtains within the bay. A consideration of the entire known 
fauna as catalogued below shows that the univalves exceed the bivalves 
by about 4 per cent. It is not evident why the proportion of gastro- 
pods should be greater in the outside than in the bay fauna. 
The waters outside the Golden Gate are more favorable to a varied 
mollusean life than are those within San Francisco Bay. This is 
shown by the greater average number of species per station than ob- 
tains in any of the regions of the bay. The most productive station, 
as far as species are concerned, is D 5789, only a short distance south- 
east of the Farallon Islands. This station yielded 25 species of mol- 
lusks that were represented by living specimens. This is more than 
twice the number (12) taken at a single station within the bay. The 
record of this most productive outside station is given below (table 1). 
TABLE 1 
RECORD OF THE Most PRODUCTIVE OUTSIDE Station (D 5789) 
No. of 
living No. of 
specimens shells 
Acila castrensis 3 1 
Acteocina cerealis -... 3 2 
Actaeon punctocoelatus 2 
Bathytoma carpenteriana 15 2 
Cadulus fusiformis 104 
Canecellaria crawfordiana 14 
Cardium centifilosum 2 4 
Columbella gausapata 11 1 
Chrysodomus tabulatus -.. 3 1 
Cuspidaria californica 6 3 
Dentalium indianorum 50 Ses 
Epitonium sawinae il 1 
Leda hamata 4 
Leda taphria —. 5 sess 
Macoma yoldiformis 1 il 
Mangila angulata 5 
Marcia subdiaphana 15 4 
Melanella micans .............------------ 3 
Modiolus politus 1 
Mytilus edulis 31 
Nassa perpinguis 7 62 
Pandora filosa -......... 3 
Phacoides annulatus 6 
Phacoides tenuisculptus 2 3 
Polinices draconis 1 1 
Volvula cylindrica 7 2 
Yoldia ensifera 7 4 
