COPEPODS OF THE WOODS HOLE KEGION" 



521 



Trunk straight, spindle-shaped, narrower than the cephalothorax ; 

 caudal rami small. First antennae 3-segmented ; second antennae 

 biramose, the exopod 2-segmented ; second maxillae and maxillipeds 

 close together and about the same size, often with a large process 

 between the bases of the second maxillae. 



KEY TO THE SPECIES (FEMALES) 



1. A single pair of posterior processes, either dorsal or ventral 2 



Two pairs of posterior processes, one dorsal, one ventral 3 



2. Posterior processes cylindrical, widely separated and dorsal to 



the ovisacs; no genital process concava (p. 521) 



Posterior processes laminate, close together and ventral to ovi- 

 sacs ; genital process present niitrata (p. 522) 



3. Ventral processes two and a half times as long as dorsal ; trunk 



twice as long as cephalothorax elegans (p. 522) 



Ventral processes little longer than dorsal; trunk only half as 



long as cephalothorax gulosa (p. 523) 



BRACHIELLA CONCAVA Wilson 



Figure 300 



BracMella concava Wilson, Proc. U. S. Nat. 

 Mas., vol. 44, p. 262, pi. 51, 1913. 



Occurrence. — A single female taken 

 from the gill arches of the sting ray 

 {Dasytatus mwmus) captured at Menem- 

 sha Bight, Marthas Vineyard, August, 

 1925. 



Distribution. — Jamaica, West Indies 

 (Wilson). 



Color. — Head and neck a clear carti- 

 lage gray; trunk yellowish; oviducts 

 white; eggs straw yellow, deepening in 

 color with development. 



Female. — Cephalothorax flexed back- 

 ward and longer than the trunk; head 

 much enlarged ; trunk short, oval, strongly 

 depressed, its dorsal surface crenate; pos- 

 terior processes attached close together on the midline, but turned 

 outward at first and then backward, thus becoming widely separated, 

 each four times as long as wide; ovisacs the same diameter as the 

 processes but twice as long. First antenna indistinctly segmented; 

 second antennae turned across the frontal margin; second maxillae 

 separate to their tips, bulla bell-shaped. Length of cephalothorax, 

 6.2 mm. ; of trunk, 4.85 mm. ; of ovisacs, 7.25 mm. 



Male. — Unknown. 



Figure 309. — BracMella oon- 

 cava: Female, lateral 



