Ecology of Pelagic Amphipoda, I — Brusca 
TABLE 4 
Day and Night Depth Distributions for 
Paracallisoma coecus 
DEPTH IN 
METERS 
TOTAL NO. 
SAMPLES 
NO. 
POSITIVE 
SAMPLES 
PER CENT 
POSITIVE 
Night 
500-900 
11 
2 
18 
900-1100 
3 
2 
66 
Day 
500-900 
16 
4 
25 
900-1100 
8 
6 
75 
nard (1954^:54) reported a depth-range of 
from 654 to 1,030 fathoms (1196 to 1884 m) 
for this species. All of the individuals col- 
lected in this present study were from shallower 
depths (520-1100 m). 
Some evidence exists that Paracallisoma coe- 
cus moves upward during the daylight hours. 
Table 4 shows that the relative abundance of 
this species was greater during the daytime, 
suggesting that some of the population was 
residing at depths greater than those sampled 
during this study. This suggestion is also sup- 
ported by the depth records stated by Barnard. 
This species was scarce from depths of less 
than 900 m. The average number per trawl 
hour in the five positive samples from depths 
less than 900 m was 5, while this value for 
the nine positive samples taken deeper than 
900 m was 36. 
Cyp ho cans an onyx Boeck 
Cyphocaris micrononyx Stebbing, 1888: 656, 
pi. 16. 
Cyphocaris anonyx Boeck, 1871: 104-105; 
Schellenberg, 1926: 210-212, figs. 2b, 5a— b, 
pi. 5, fig. 2; Shoemaker, 1945: 187, figs, la-b; 
Barnard, J. L., 1954^: 53; Waterman, 1939: 
256-279. 
A total of 115 individuals was recovered 
from quantitative samples during this study. 
Shoemaker (1945:187) recorded this species 
at depths of from 600 to 1,000 fathoms (1161 
to 1935 m), and a single specimen was re- 
ported by J. L. Barnard (1954^:53) taken in 
a net tow from 560 to 640 fathoms (1084 to 
1239 m). Waterman et al. (1939:268) re- 
385 
ported Cyphocaris anonyx taken at depths of 
from about 200 to 1000 m. This present study 
revealed individuals of this species in 27 sam- 
ples at depths of from 150 to 1100 m. Water- 
man also recorded a large portion of the popu- 
lation moving from 600 m in the daytime to 
about 200 m at night. Some evidence for this 
migration is found in the capture times and 
depths of this present study, but it is not 
conclusive. 
Cyphocaris richardi Chevreux 
Cyphocaris Richardi Chevreux, 1905: 1-5, 
figs. 1-2; Chevreux, 1916:1. 
Cyphocaris richardi Schellenberg, 1926:206- 
209, figs. 2a, 3 a-e, Aa-d, pi. 5, fig. 1; Barnard, 
K. H., 1932:35; Stephensen, 1933:4-5; Shoe- 
maker, 1945:187-189, fig. id; Barnard, J. L., 
1954^:54, pis. 2-3; Barnard, J. L., 1961:32; 
Barnard, J. L., 1962:24; Bernstein and Vino- 
gradov, 1955:212-213, figs. 2-3; Bernstein and 
Vinogradov, 1958:221. 
Collected in 28 trawls, a total of 193 indi- 
viduals was taken in quantitative aliquots. 
Positive samples ranged in depth from 500 to 
1100 m. Table 5 illustrates the day and night 
depth distributions for Cyphocaris richardi. 
From these data it can be seen that this species 
was rather evenly distributed between 500 m 
and the depth of the deepest samples taken 
(1100 m). There is no conclusive evidence 
of any vertical movement. 
Suborder hyperiidea 
Family platyscelidae 
Platyscelus serratulus Stebbing 
Platyscelus serratulus Stebbing, 1888:1470; 
Stephensen, 1925:215-218, chart 31; Chev- 
reux and Fage, 1925:422, fig. 414; Barnard, 
K. H., 1930:437; Pirlot, 1930:37; Barnard, 
K. H., 1932:298; Shoemaker, 1945:259; 
Hurley, 1956:21-22. 
Platyscelus serratulus occurred in 6 samples 
during this study, a total of 8 specimens was 
recorded at depths ranging from 170 to 927 
m. Stephensen (1925:215-218) reported find- 
ing this species at the surface at night. Al- 
though only a few individuals were taken dur- 
