38 LIVERPOOL BIOLOGICAL SOCIETY. 
doubt of great protective service. The right anterior 
antenna of the male is shown in Pl. VI., fig. 2, with its 
strongly beaked rostrum at the base. The strong hooked 
spines in this antenna and the deep saw-like serratures on 
the seventeenth and eighteenth joints are very diagnostic. 
The termination of one of the swimming feet, with its 
finely serrated edge, is shown on fig. 3, and the fifth pair 
of feet of male and female on figs. 4 and 5. It will be 
seen that the right foot of the male’s fifth pair is provided 
with a large moveable spinous claw, and is well adapted, 
in conjunction with the powerful right antenna, for clasp- 
ing the female during copulation. The fifth feet of the 
female are each provided with a pair of pointed claw-like 
spines (fig. 5), and are unlike those of any other Copepod 
with which I am acquainted. 
The presence and distribution of Copepoda in our seas 
are most vitally interesting, forming, as they unquestion- 
ably do, by far the largest proportion of the life of the 
ocean. And being themselves of the utmost purifying 
utility as scavengers, they transform the refuse, by their 
internal biological and chemical laboratories, into food for 
higher orders of ocean denizens—these again furnishing, 
in illimitable quantity, the food of man. 
EXPLANATION OF PLATES. 
PuaTE IV. 
Fig. 1. Hurytemora hirundo (Giesbrecht), entire animal, 
female. 
Fig. 2. Do. do. right antenna, male. 
JEU Sos Fae Do. do. right and left foot, male. 
wissd: 4 Do: do. fifth foot of female. 
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