Copepods in Southeastern Pacific — Grice and Hulsemann 
333 
Figs. 63-74. Lophothrix gigas (A. Scott), female. 63, Dorsal view; 64, lateral view; 63, anterior end 
of head, dorsal view; 66, anterior end of head, lateral view; 67, rostrum; 68, posterior end of thorax and 
abdomen, dorsal view; 69, posterior end of thorax and abdomen, lateral view; 70, first foot; 71, endopod of 
second foot; 72, endopod of third foot; 73, endopod of fourth foot; 74, fifth feet. 
by fine line, fourth and fifth thoracic segments 
incompletely fused. Head in dorsal view tri- 
angularly rounded, in lateral view with low 
crest. Posterior lateral corner of last thoracic 
segment broadly triangular ending in a point. 
Fifth thoracic segment and ventral portion of 
fourth with pitted surface. Rostrum large, 
directed downward and backward; swollen in 
its distal half, tapering into two separate points. 
Genital segment about as long as the rest of the 
abdomen produced ventrally, slightly overhang- 
ing second abdominal segment. Furcal rami 
short, divergent. First antenna 24-segmented, 
segments 8 and 9 incompletely fused, reaching 
third abdominal segment. Exopod of second 
antenna slightly longer than endopod. Second 
maxilla distally with sensory appendages. Exo- 
pods of first to fourth swimming feet 3-seg- 
mented; endopod of first foot 1 -segmented, of 
second foot 2 -segmented, of third and fourth 
feet 3-segmented. Second and third endopodal 
segments of second to fourth foot armed with 
spines on their posterior sides. Fifth foot 3-seg- 
mented. Terminal segment bearing 4 setae; 1 
originating in the middle of the outer margin, 
1 on the inner margin near the distal end, and 
2 on the distal end. Inner seta nearly 3 times 
the length of outer seta. Total length 7.91- 
8.66 mm. 
remarks: The large size, the pointed fifth 
thoracic segment, and the shape of the fifth pair 
of feet distinguish Lophothrix gigas from all 
other species in the genus. 
Vervoort (1965) recognized that the im- 
mature male described by A. Scott (1909) as 
Brachycalanus gigas belongs to the genus 
Lophothrix. Vervoort mentions also that he 
found an immature male and an adult female 
of Lophothrix gigas in the "Snellius” collection. 
We obtained seven females of this large species. 
After kindly comparing drawings of one of our 
females with the female from the "Snellius” 
