8 BEITISH COPEPODA. 



short and exquisitely plumed antennae, and (in the 

 male) by the conspicuous posterior abdominal spine. 

 It is certainly one of the most common, as it is also 

 amongst the most beautiful, of British Copepods. The 

 following are some of the localities in which I have 

 taken it : Abundantly on a sandy bottom off Seaton 

 Carew (Durham), four fathoms ; off Marsden, Sunder- 

 land, and Seaham, twenty to thirty fathoms ; Clifden 

 Bay, Ireland, four fathoms ; in tide-pools, Aranmore 

 (Ireland) ; Lough S willy, two fathoms ; off St. Mary 

 and St. Agnes, Scilly Islands, twenty to forty fathoms ; 

 Shetland (Rev. A. M. Norman) ; on weeds at Bell 

 Rock Lighthouse (Mr. E. C. Davison). 



Genus 2. ECTINOSOMA, Boeck (1864). 



Body much elongated, slender; abdomen not 

 separated from the thorax by any distinct constric- 

 tion, and remaining unflexed on the body after death 

 (PI. XXXVI, fig. 1). Head small, and united with 

 the first thoracic segment. Anterior antennae (fig. 2) 

 very short, much attenuated towards the apex, 5 7- 

 jointed, bearing numerous long setae. Posterior an- 

 tennae much larger and stronger (fig. 3), 3-jointed, 

 and having attached to the first joint a long 2- or 3- 

 jointed secondary branch; the last joint bears several 

 strong, spine-like, plumose hairs. Mandible (fig. 4) 

 slender, deeply cleft at the apex ; palp large, 2-jointed, 

 bearing several long setae and a short, simple, secon- 



