COPEPODS OP THE WOODS HOLE REGION 



377 



ERGASILUS LABRACIS Krffyer 

 FlQXJBEJ 231 



Ergasilus labracis Kr0teb, Naturh. Tidsskrift, ser. 3, vol. 2, p. 303, pi. 11, fig. 2, 

 1863.— Wilson, Proc. U. S. Nat. Mus., vol. 39, p. 329, pi. 41, 1911. 



Occurrence. — Found often in great abundance on the gills of the 

 striped bass {Roceus lineatus) at Woods Hole. 



Distribution. — Baltimore, Md. (Kr0yer) ; Philadelphia fish mar- 

 kets (Leidy) ; Washington, D. C, fish markets (Dr. H. M. Smith) ; 

 Franklin, Va. (Worth). 



Color. — Mature females are milky white on the dorsal surface 

 and opaque, young females have a bluish tinge and are more trans- 

 parent; both show a varie- 

 gated pattern of blue pigment 

 dots along the center of the 

 ventral surface on either side 

 of the midline. 



Female. — Head fused with 

 first segment, the two more 

 than half the entire length, 

 projecting a little anteriorly 

 and almost squarely truncated 

 posteriorly ; genital segment 

 as wide as the fifth segment 

 and as long as the abdomen 

 and caudal rami together. 



Basal segment of second antenna swollen to twice the width of the 

 second segment, apical claw with several small teeth on the inner 

 margin near the base. Exopod of fourth leg made up of a single 

 segment ; each fifth leg lacking but replaced by a single seta. Total 

 length, 1-1.25 mm. 



Male. — Unknown. 



Remarks. — This species is apparently confined to the striped bass, 

 upon which it may be found in almost any fish market along the 

 entire Atlantic coast. 



ERGASILUS CENTRARCHroARUM Wright 



Figure 232 



Ergasilus centrarchidarum Wright, Proc. Can. Inst., new ser., vol. 1, p. 243, pi. 

 1, 1882.— Wilson, Proc. U. S. Nat. Mus., vol. 39, p. 331, pi. 42, figs. 50-58, 

 1911. 



Occurrence. — Females were obtained from the gills of the smelt 

 {Osmerus mordax)., in the vicinity of Woods Hole by Vinal Edwards. 



Figure 231. — Err/asilus lairacis: a. Female, dor- 

 sal ; J), female, fourth leg 



