COPEPODA. 35 



10. X. ATLANTICUS. 

 X. atlantkus, Wolfenden, Jour. jMar. Biol. Assoc, April, 11)04. 



Size 2"5 mm. ; anterior aiitenuEe much shorter than thorax and very thick basally, 

 abdominal segments prickly and hirsute, feet very spinulose ; fifth of three segments, 

 distal the largest, with four large articulating spines, two apical, two lateral ; all 

 segments very spinulose ; furcal rami as broad as long, and Re of posterior antennas 

 much longer than Ri. (West of Ireland.) 



11. X. OBTOSUS. 



X. obtusus, Farran, Ann. Rej). Fish., Ireland, ] 1)02-03, pt. ii., App. 11. (lOO.'i), p. 40. 



Size 2 '4 mm. Furcal rami little longer than broad, anterior antennae reach genital 

 segment, feet very spinulose. Fifth feet, three segmented, spinulose, and with two 

 terminal and two lateral spines on last segment ; second joint longest, and spinulose on 

 both margins. (Atlantic. Ireland.) 



12. X. PINGUIS. 



X.p'mguis, Fan-an, Ann. Rep. Fish., Ireland, ll)o2-03, pt. ii., App. II. (1I)0,">), p. 40. 



Size 4'5 mm. Head imperfectly separated from thorax ; lateral processes of 

 last segment blunt ; furcal segments slightly longer than broad ; anterior antennae 

 short, not as long as thoi'ax ; rami of posterior antennae short and broad ; feet spinulose. 

 Fifth feet of three segments, and two lateral and two apical end spines ; surface of 

 third and margins of first (inner) and second (outer) spinulose. (Atlantic. Ireland.) 



13. X. GREENI. X. MUTICUS. 



X. greeni, Farran, Ann. Rep. Fish., Ireland, 1002-03, pt. ii., App. II. (190.")), p. 40. X. muticus, Sars, 

 Bull. Mus. Monaco. 



Size 5*30-6 mm. ; last two segments of thorax united, last segment with obtusely 

 triangular margins ; furcal segments short, broader than long ; anterior antennae little 

 longer than body. Fifth feet small, two-jointed (Sars), or three-jointed (Farran), without 

 spines on inner margin ; last joint with three small apical spines. (Atlantic. Ireland.) 



14. X. TYPICUS. 



Amallophora typica, Scott, Tr. Linn. Soc. (2), VI. (1894), p. .54. 



Only the i known; 27 mm. long; anterior antennae, twenty segments; right 

 fifth foot short and three segments, left like that of X. agilis. 



