COPEPODS OF THE WOODS HOLE EEGIOF 



347 



Color. — Body grayish white; contents of digestive canal bluish 

 green. 



Female. — Head separated from first segment, wider than long; 

 first four thoracic segments diminishing slightly in width, but about 

 the same length ; fifth segment abruptly contracted to half the width 

 and one-fourth the length of the fourth segment. Urosome one- 

 fourth the length of the metasome ; 

 caudal rami as long as the last two 

 abdominal segments combined. 

 First antennae 7-segmented; sec- 

 ond antenna tipped with a single 

 stout claw; fifth leg 3-segmented, 

 first and second segments with an 

 outer distal seta, end segment witli 

 one apical, two outer setae, and \\ 

 subapical group of spines. Total 

 length, 2.75-3 mm. 



Male. — Metasome spindle- 

 shaped, tapering anteriorly and 

 posteriorly; fifth segment but lit- 

 tle narrower and fully as long as 

 fourth ; urosome half the length of 

 the metasome; genital segment 

 considerably enlarged ; posterior margins of the genital and first two 

 abdominal segments denticulate. Maxillipeds 2-segmented, with a 

 long and powerful terminal claw ; other appendages like those of the 

 female. Total length, 1.5-1.75 mm. 



Remarks. — The female of this parasite sometimes lodges in the gill 

 tubes of the clam and may then be detected by local swellings of the 

 tube corresponding to the length of the copepod parasite. 



MYICOLA MAJOR (WUliams) 



FiGUKH 208 



Lichomolgus major Williams, 37th Ann. Eep. Comm. Inland Fisheries Rhode 

 Island, p. 77, pi. 3, 7 figs., 1907. 



Occurrence. — Both sexes were obtained by Williams from the 

 mantle cavity of the common clam {Mya arenaria)^ the quahog clam 

 {Venus iiiercenaria) ., and the sea clam {Mactra solidisshna) ., in 

 Narragansett Bay. 



Distribution. — It has not as yet been found in any other locality. 



Color. — Body fairly transparent, of a uniform grayish or pinkish. 



Female. — Metasome cylindrical; head fused with first segment 

 and about as long as wide; second, third, and fourth segments 

 tapered but little ; fifth segment abruptly reduced to half the width 



FiGUEB 207. — Myicola metisiensis: a. Fe- 

 male, dorsal (after Wright) ; i, male, 

 maxilliped ; c, female, fifth leg 



