222 University of California Publications in Zoology | Vou. 14 
varieties are known to range north of San Francisco, whereas 154 
oceur south of that place. These figures are of less value in deter- 
mining the relationships of the fauna to other West Coast faunas than 
are those derived according to a method used by Sumner et al. (1911, 
p. 184). Those authors compare the number of *‘ predominantly north- 
ward ranging’’ species with the number of southward ranging forms. 
They define ‘‘predominately northward ranging’’ species as one, 
‘‘whose range (in latitude) to the northward on our coast is at least 
twice as great as is its range to the southward.’’ Applying this 
method to our fauna as catalogued gives 77 species as predominantly 
northward ranging ; 55 as predominantly southward ranging ; 37 whose 
known ranges are nearly equal to the north and south of San Fran- 
cisco; 14 which are known only from San Francisco, and 11 species 
that cannot properly be classified, since their ranges are imperfectly 
known. This indicates, if the faunas north and south of San Francisco 
are about equally well known, that the local fauna has closer affinities 
with the northern fauna than with that to the south. 
Two new species of mollusks have been discovered as a result of 
the dredging operations of the ‘‘Albatross.’? They have been de- 
seribed by Dr. Bartsch under the names of Odostoma franciscana and 
Turbonilla franciscana. 
The mollusean fauna of this region includes several exotic species, 
most of which have inadvertently been introduced with young oysters 
TABLE 3 
ReEcorD OF THE Most Propuctive BAy Station (D 5796) 
No. of 
living No. of 
specimens shells 
(Car dim COND IS) eee co cen eee 17 18 
Columibellay ran sap arta sere cseeetee ees. 0 5 
Mya californica ............ Ne OE ee 0 10 
ITE cXoy cells), co eM (CPW NS eM a ete 0 5 
Macoma nasuta ~...... 0 3 
Mona aerosc his asec eece meena eee 0 1 
Miryitallis)<@ Gili) 22-2 ceee arc -neaee ence eee 0 1 
INassafoss arta .-.c 5 eae erate eee recta 0 1 
INASSa! (MONG C a) oeea 22. c noc ceeneseeceeeease eee enceaes 2 
Ostrea lurida 10 
Paphia staminea 1 
Schizothaerus nuttalli 2 
Siliqua nuttalli ........... 1 
Tellina salmonea 0 2 
Thais Jamellosa 1 27 
Zirfaea gabbi 0 1 
