458 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 49. 



dilated in front and laterally, the lateral dilatations not very promi- 

 nent, witli two minute lateral spines at about one-third its length. The 

 second and third segments are about equal in length, and the furcal 

 rami are somewhat longer than these 

 segments, and are ciliate on the inner 

 margins. 



The antennae are 25-segmented and 

 extend beyond the furca. 



The right antenna of the male is 

 much swollen anterior to the geniculat- 

 ing joint. The antepenultimate seg- 

 ment (fig. 3) bears a very short hook- 

 shaped process. 



The first basal segments of the female 

 fifth feet (fig. 4) are armed with rather 

 F1G.3.-DIAPT0- gj^aii spines. The lateral hahs of the 

 ENsis. ter- second basal segments are rather long 

 and slender. The exopodite consists of 



MINAL SEG- 

 MENTS OF AN- mi 1 1 J* 1 1 



TENNA OF two segments. 1 he hooK oi the second 



MALE, X 445. 



Fig. 4.— Diaptomus vir- 

 GiNiENsis. Fifth 



FOOT OF FEMALE, 



X 875. 



segment is stout and denticulate on the 

 inner margin. The outer angle of the second seg- 

 ment bears two spines, the inner unusually long, 

 being about twice'the length of the outer. The endopodite is 1 -seg- 

 mented, and is somewhat longer than the first segment of the exop- 

 odite. It is setose on the inner margin of the tip, and the tip is 

 armed with two rather stout spines. 



The spines of the first basal segments 

 of the male fifth (fig. 5) feet are of mod- 

 erate size. The second basal segment 

 of the right foot is rather elongate, its 

 distal end twice as wide as its proximal. 

 The inner margin is convex, the outer 

 straight, making a rather sharp bend 

 near its distal end. The lateral hair is 

 situated at about three-fourths its 

 length. The first segment of the exop- 

 odite is about as broad as long, its in- 

 ner and outer margins convex, and bears 

 a triangular hyahne projection on its 

 inner margin, which is continued as a 

 shelflike projection on its posterior sur- 

 face. The second segment is approx- 

 imately four times as long as broad, con- 

 cave on the imier margin and convex on 

 the outer. The lateral spme is stout, 

 about one-third the length of the seg- 



•, .. , 1 ■! J • 1 I. •, Fig. 5.— Diaptomus vraGiNiENsis. 



ment, and situated about midway of its ^oot of male, x 445. 



Fifth 



