ws) TG 
Th? FO 8 8 66a 61 (16 
26, 1928, 7.20 + an. or 
26, 1928, 10.25 PM to 1 
on ty 
C |tocati ion of tow 
238 Leng tn or te W miles 
loncaea curvata 
| similis 
iParacalanus parvus 
‘Pleuromamma gracilis 
Pseudocalany is minutus 
Scolecitnrix danae 
Jndinula darwini 
Undeuchaeta major 
' Acroe alanus er acl 
Clausocalanus arcu decks 
Tfurcatus 
|Microsetella rosea 
| Neocalanus gracilis 
| Oithona brevicornis 
, Similis 
Calanus tonsus 
’ 
' be 
Se deal aeremieemiaats 0 
| 
} 
i 
ee 
csi 
| 
oko 
r a Nt SES Ne RI Ne i A PSR NA 
; 
These three surface tows were taken the same night but a few miles 
The first tow from 5 1) the iate afternoon yielded seven 
species » the second tow from 7 to 10 in the evening yielded only two species 
and the third tow over midnight yielded fifteen species-« It is also 
worthy of note that the third tow, although shorter than the second, yielded 
a volume eight times as large and this volume was four and a half times that 
of the first tow although the latter was twice as longe That the midnight 
tow should contain twice the number of species of either of tne others is 
however exactly what would be expected as a result of nocturnal migratione 
The species round in it that were not present in the other tows are the 
ones that require a longer time to reach the surfacee This may be due to 
Slower progress or to a longer distance traversed, Undeuchaeta probably com- 
ing under the latter alternative, while Oncaea mignt well represent the form- 
ere 
Clausocalanus and Oithona comprised 99% of the first tow, the second 
tow was evenly divided between Oitnhona and Calanus 5 while no single species 
of the third tow stood out with any prominence Nine of the species (56%) 
were each confined to one of the tows and not found in the other two, and only 
a single species was vresent in all three tows. These three tows thus present 
considerable diversity in the surface distribution of the copepods. 

