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 
FACILE CAS TEETIS1 Spee eee ee ee ee 3 1 
Acteocina cerealis 3 2 
Actaeon punctocoelatus —....2.20.-222-2.2-- 2 ate 
Bathytoma carpenteriana ........-..--.--.------- 15 2 
Calc SMEs ek Onna Speen 104 
Cancellaria crawfordiana ..........-.--.-2-..-.-- 14 aes 
Cardium centifilosum 2 4 
Columbella gausapata -.....-...220---221-s-e--- 11 1 
Chrysodomus tabulatus -. 3 1 
Cuspidaria californica .... 6 3 
Dentalium indianorum .- 50 
Hpitomium sawimae —....2.2 eee 1 1 
Theda: Wamatay 2 so ee eee ees 4 
ATU Clea tiek ye haere ee eee 5 
Macoma yoldiformis ...........-..------------------ 1 1 
IWikkimyetiley, ERNGAUIENIE, ceccceccenozencencecmesoerceetsscee Skene 5 
Marcia subdiaphana —_.....----------- 15 4 
Melanella micans 3 2 
Modiolus politus fo a 
Mytilus edulis ..... os oll 
Nassa perpinguis - 74 62 
Pandora filosa -.......... 3 3 
Phalcoxd espana wll aus ieee ee eee eee 6 
Phacoides tenuisculptus -—..........---..------.-- 2 3 
Polinices draconis .........----------------------------- ils 1 
AVio lvl ay cryin Cis Calg eeseeereee eens eenceeenseeennen 7 2 
Woldiaivensit era coccsecce co tereeeereeomeerrsoneoe 7 4 
