Vou.2]  Esterly—Copepoda of the San Diego Region. A by Gri 
Allied to P. abdominalis, but the front of the head anterior 
to the rostrum is prolonged into a prominent process (fig. 340). 
Coloration: As in the other species. 
Length: Female, 4.1-4.5 mm. 
Occurrence: San Diego, July 31, 1903, one female; June 23, 
1904, one female; taken also December 23, 1903, on ‘‘Banks.’’ 
The occurrence of the male is uncertain; large male animals have 
been taken with the characteristic shape of xiphias, but I cannot 
say definitely whether they belong to this species or not. 
2. Genus Metridia Boeck. 
Metridia Boeck, 1864, p. 13. 
Paracalanus Brady and Robertson, 1878, p. 126. 
Metridia Giesbrecht, 1892, pp. 61, 339, 749; 1897, p. 254; 1898, 
p. 105. 
Metridia Dahl, 1894a, p. 10. 
Metridia Wheeler, 1899, p. 175. 
Metridia Wolfenden, 1904, p. 125. 
(See also T. Scott, 1893, p. 42, pl. 3, figs. 8-20.) 
Closely allied to Pleuromamma, but is without the lateral pig- 
ment knob. Terminal bristle of outer ramus of third pair of 
normal form; swimming feet of the male (especially the second 
pair) corresponding with those of the female. Furea 2 to 5 times 
as long as broad. 
1. Metridia lucens Boeck. 
Metridia lucens Boeck, 1864, p. 14. 
Paracalanus hibernicus Brady and Robertson, 1873, p. 126. pl. 8, 
figs. 1-3. 
Metridia armata Brady, 1878, p. 42. 
Metridia hibernica Giesbrecht, 1892, pp. 340, 357, pl. 33, figs. 2, 
12; 16, 22, 28,36, 39. 
Metridia lucens Dahl, 1894, p. 11. 
Metridia lucens Giesbrecht, 1898, p. 106. 
2 Cephalothorax 124 times as long as the abdomen; lateral 
angles of fifth thoracic segment slightly pointed. Genital seg- 
ment somewhat shorter than the two last abdominal segments 
together, the anal segment about 34 as long as the preceding. 
Furea shorter than the last abdominal segment and twice as 
long as broad. The anterior antennae reach back hardly to 
posterior margin of the genital segment. Terminal bristle of 
end joint of outer ramus of fourth foot lttle over 14 as long 
