ENHYDROSOMA. 97 



nearly equal size, but short, being scarcely longer than 

 the width of the thorax ; the margins of all the joints 

 of the outer branches are fringed with spine-like setge, 

 and the apical spines are large and strong. The fifth 

 pair, in the female (fig. 11), has the basal joint well 

 developed and forming a large internal segment, which 

 bears five marginal setse ; outer branch subovate, 

 having four large and two small setae ; the margins of 

 both joints finely ciliated ; the tail-segments have at 

 the apex one stout seta about equal in length to four 

 of the abdominal joints, and on the lateral margins are 

 also three or four minute setae. Length, -^nd of an 

 inch (1*1 mm.). 



This is a very distinct and at the same time one of 

 the least common of British species. I for a long 

 time knew it only from two specimens, one found on 

 a Sponge in Westport Bay, and one taken amongst 

 Algce at St. Mary's, Scilly ; but more recently I have 

 found several specimens in a collection of Copepoda 

 washed from the roots of Algce gathered in Round- 

 stone Bay. 



\ 

 Genus 21. ENHYDROSOMA, BoecJc. ' 



* 



(Boeck, Nye Slaegter og Arter af Saltvands-Copepoder, 1872.) 



Body subcylindrical ; first pair of antennae short and 

 stout, 5-jointed ; second pair nearly as large as the 

 first, 2-jointed, secondary branch small, 1-jointed; 



VOL. LI. 



