338 University of California Publications in Zoology (Vou. 9 
though shown by only one haul; that, allowing for this condition, 
there is clear evidence of a regular diurnal migration. 
(b) With the horizontal closing nets (tables 28 and 29) the 
day plurimum is shown to be at 100-160 fathoms; from 6 p.m. 
to 2 a.m. it does not go lower than 12 fathoms, but between 2 and 
6 a.m. it is at 100-160 fathoms. 
(ec) With the vertical closing nets we found (tables 30 and 
31) that there is evidence of diurnal migration, the day plurimum 
being between 200 and 150 fathoms, while at night it is at 100-75 
fathoms. 
10. The following species did not come to the surface: 
Euchaeta tonsa, Euchirella galeata, Gaetanus unicorns, Pleuro- 
mamma abdominalis, Scolecithria frontalis, Scolecithrix magna. 
As a group, these six species are most abundant below 200 fathoms 
during the day and above 200 fathoms during the night (tables 
52 and 53). 
11. The other ten species (Huchirella pulchra and E. rostrata, 
Gaidius pungens, Labidocera trispinosa, Pleuromamma abdomin- 
alis, P. gracilis and P. quadrungulata, Rhincalanus nasutus, 
Scolecithrix persecans, Undeuchaeta bispinosa) were taken at the 
surface, but in so few hauls that an extensive analysis of them is 
not practicable. So far as the evidence goes, they are, with three 
exceptions more abundant at the surface at night, as can be seen 
in table 55. The exceptions are nine animals belonging to three 
species and there is nothing whatever to show why they should be 
found at the surface. The hauls with the closing nets show that 
these species, like the others, move upward during the night, as 
may be seen in summary in table 54. 
Transmitted February, 1912. 
OCCIDENTAL COLLEGE, 
Los ANGELES, CALIFORNIA. 
