COPEPODS OF THE WOODS HOLE REGION 615 



14. Head fused with metasome, armed with 6 knobs, 2 anterior, 



2 dorsal, 2 ventral; genital segment with 8 dactylose processes; 



no legs; mouth of fishes ? Strabax Nordmann, 1864 



Head separated; metasome fused and unsegmented; urosome 

 2-segmented with caudal rami; 2 pairs of legs, no horns, 

 knobs, or processes; gills of fishes ? Blias Kr0yer, 1863 (p. 493) 



Head separated; metasome with 1 or 2 free segments, paired 

 horns or lateral processes and unpaired dorsal knobs or 

 laminae 15 



Head fused with first segment, separated from second segment 

 by a short neck; 1 or more pairs of legs and processes, but 

 no knobs 16 



Head separated; metasome usually 4-segmepted; no horns or 



dorsal knobs, but paired lateral processes and 2 pairs of legs 17 



15. First 2 segments free, rest of thorax fused with lateral knobs and 



dorsal laminae; legs uniramose, end segments boot-shaped; 



gills of fishes ? Chondracanthopsis, new genus (p. 508) 



First segment only free, rest of thorax fused with 3 pairs of 

 lateral processes turned ventrally; head deflexed; legs bira- 

 mose; gills of fishes ? Chondracanthodes, new genus (p. 506) 



First segment only free, rest of thorax fused without lateral 

 processes; a horn at each anterior corner of head; 1 pair of 

 legs; gills of fishes 9 Pseudochondracanthus Wilson, 1908 (p. 495) 



16. Metasome segments distinctly separated, each with lateral 



processes; second segment with a pair of dorsal horns; 1 pair 



of legs; gills of fishes 9 Juanettia Wilson, 1921 



Metasome segments completely fused, without lateral processes; 

 no dorsal horns; second antennae tripartite; 2 pairs of leg 

 rudiments; gills of fishes 9 Triphyllacanthus Oakley, 1930 



17. Head smooth, without barbs or processes; metasome also with- 



out processes except 1 pair at posterior corners of the fourth 



segment; gills of fishes 9 Acanthochondria Oakley, 1927 (p. 500) 



Head with lateral barbs or posterior processes; metasome also 

 with paired processes, dorsal, ventral, or lateral, any 2 or 

 all 3; gills of fishes 9 Chondracanthus La Roche, 1811, (p. 497) 



18. Head more or less separated from trunk; latter with 3 pairs of 



lateral processes; abdomen 1-segmented; second antennae 



with terminal claws; gills of fishes 9 Diocus Kr0yer, 1863 



Head fused with metasome; latter with 1 pair of lateral pro- 

 cesses bearing knobs and lobes; second antenna a multifid 

 horn; gills of fishes 9 Tanypleurus Steenstrup and Liitken, 1861 



19. Leg rudiments entirely lacking; no abdomen; body segments 



indistinct; each caudal ramus conical and divided distally; 



gills of fishes & Pseudochondracanthus Wilson, 1908 (p. 495) 



Two pairs of leg rudiments, biramose, rami 1-segmented, exo- 



pods with spines; second antenna 3-segmented, end segment 



with outer accessory claw; gills of fishes. 



cf Chondracanthodes, new genus (p. 506) 



Two pairs of leg rudiments, uniramose, 2-segmented, setose 20 



Two pairs of leg rudiments, uniramose, 1-segmented, setose 21 



Five pairs of leg rudiments, anterior pairs biramose 24 



