186 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Length of male, 1.8 to 2 mm. ; of female, 2.25 mm. 
The males of this species, which I take pleasure in dedicating to my friend, Prof. H. C. Burnpus, 
appeared in considerable numbers in tow taken off Fish Commission wharf July 10 and 11, 1899, and 
again in Vineyard Sound, near Gay Head, Marthas Vineyard, on the latter day. The single female 
specimen from which the above description was drawn was found in some tow collected by Mr. 
Vinal N. Edwards at Woods Hole, December 15, 1898. 
(X bumpusii is remarkable in two respects. First, it differs from all the known species of Corynura 
in having 3 instead of 2 jointed inner rami on first pair of feet. Giesbreclit’s diagnosis of the genus 
should be widened to receive this species. Second, the occurrence of a Corynura in the Atlantic has 
not before been recorded. The five species hitherto described are all from the east coast of Asia, thus : 
C. forcipata Giesbr. is from Amoy; C. denticulata Giesbr. and C. recticauda Giesbr. are from Assab; 
C. yracilis Brady and C. barbata Brady from the'Philippines. 
Suborder P0D0PLEA. 
Family CYCLOPIDJE. 
OITHONA Baird. 
Female : Cephalothorax and abdomen with 5 segments ( first and second abdominal segments fused) ; 
front usually terminating in a pointed, beak-like process; genital opening lateral. Anterior antennae in 
part indistinctly jointed, with long bristles, without sestlietasks. Posterior antennae 2-jointed (first 
basal joint fused with secoud, first joint of inner ramus with second), with indistinct bipartition of 
second joint; outer ramus wanting. Mandible elongated, with small, 1-jointed inner, and 4-jointed outer 
ramus and denticulate blade. Maxilla with well-armed masticatory process (first inner lobe) and with 
uncinate bristles even on other portions of inner margin; rami 1-jointed, inner ramus small, first outer 
lobe rudimental. Maxillipeds slender, with powerful, prickly bristles, the posterior with 2-jointed 
inner ramus. Feet with 3-jointed rami ; fifth foot very rudimental, on either side reduced to 2 bristles. 
Male: Front obtuse. First aud second abdominal segments separated ; furcal bristles abbreviated, 
anterior antenme grasping organs each geniculating at two points, with a terminal msthetask ; feet 
with somewhat aberrant bristles. 
22. Oithona plumifera Baird. 
Female: Front ending in a pointed beak, which is bent ventrally somewhat, but is still visible 
from dorsal aspect; furea shorter than anal segment, nearly 3 times as long as broad; its outermost 
bristle about 3 times as long as furca. Anterior antennre reaching to posterior border of fourth 
abdominal segment. Second basal joint of mandibles with 2 hook like bristles. Inner ramus of 
maxillae with a few minute bristles. Outer ramus of first pair of feet with 1, 1, 2, the third with 1, 0, 2, 
the fourth with 0, 0, 2 outer marginal bristles; proximal outer bristle of third outer ramus of third and 
fourth pairs reduced. 
Male : Genital segment broad. Proximal joint of distal portion of anterior antenme with a semi- 
circular projection on inner margin. Third joint of outer ramus of first and fourth pairs of feet with 
2, the second and third with 3 outer bristles. 
Coloration: Very transparent, with ferruginous pigment very variously distributed through 
cephalothorax, especially in oral region, sometimes forming symmetrical spots in thorax, more rarely 
in abdomen, often in long bristles of anterior antennae, furca, and feet; other individuals are quite 
colorless except for the ruby-red eye. 
Length of female, .01 to 1.5 mm; of male, .075 mm. 
Three female specimens taken in the Gulf Stream, 70 miles south of Marthas Vineyard, July 25, 
1899. These specimens were colorless. 
23. Oithona similis Claus. 
Female: Front ending in a hooked, pointed beak which is bent ventrally at a right angle and 
hence not visible from dorsal aspect; genital orifices situated further posteriorly than in other 
species of the genus; furca shorter than anal segment, nearly 21 times as lorg as broad, its outermost 
bristle about as long as furca. Anterior antenna: scarcely reaching to genital orifices. Second basal 
