— a ee 
vou.2] Esterly.—Copepoda of the San Diego Region. 207 
15. Forehead pointed (fig. 53a); body broad; outer ramus of pos- 
terior antenna 1-jointed... ... 2.5 coc cee see cen ce eee eee esas 17 
16. Furea with separate rami (about twice as long as broad) and 
bristles much shorter than body (fig. 53@)............-- *Buterpe 
16. Rami of the fuca very short and with the two unusually long 
Vayerss Ales) Feoee eel shay qelave) semVerolreenat IbhiNe Goo Gap oc odDDUDoOUDOoC Aegisthus 
Fam. CYCLOPIDAE. 
1. Genus Oithona Baird. 
Oithona Baird, 1843. 
Scribella Dana, 1847, p. 279; 1848, p. 19. 
Oithona Dana, 1852, p. 1097. 
Oithona Claus, 1863, p. 104. 
Oithona Brady, 1883, p. 97. 
Oithona Giesbrecht, 1892, pp. 77, 537, 753; 1896, p. 324. 
Oithona Wheeler, 1899, p. 186. 
® Anterior and posterior parts of body composed of five 
segments, first and second abdominal segments fused (fig. 50a). 
Genital opening lateral. Anterior antennae rather obscurely 
jointed, bristles long; posterior antennae 3-jointed, outer ramus 
absent. Inner ramus of mandible small, 1-jointed, outer ramus 
4-jointed; blade dentate. Rami of maxilla 1-jointed, inner 
ramus small. Maxillipeds slender, bristles strong, spinous; 
inner ramus of posterior maxilliped 2-jointed. Rami of swim- 
ming feet 3-jointed. Fifth pair very rudimentary, being reduced 
to two bristles on each side. 
4 Front of head blunt (fig. 51a) ; first and second abdominal 
segments not fused (fig. 500, 51a), bristles of furea_ short. 
Anterior antenna are grasping organs, geniculating at two 
places. Swimming feet somewhat irregular in number and 
arrangement of bristles. 
1. Oithona plumifera Baird. 
Oithona plumifera Baird, 1848. 
Oithona plumifera Dana, 1852, p. 1099, pl. 76, figs. 4a-e. 
Scribella scriba Dana, 1849, p. 279. 
Githona spinirostris Claus, 1863, p. 105. 
Oithona plumifera Giesbrecht, 1891, p. 475; 1892, pp. 537, 548; 
pl. 4, fig. 10; pl. 34, figs. 12, 13, 22, 25, 27-29, 32, 33, 
44-47; pl. 44, figs. 1, 7, 12-15. 
Githona plumifera Wheeler, 1899, p. 186, fig. 22. 
2 Front ending in a somewhat ventrally directed, pointed 
beak, but visible in dorsal view. Furea shorter than anal seg- 
