432 MESSES. T. AND A. SCOTT — REVISION OF THE BRITISH COPEPODA 



secondary joint is broadly subcylindrical, with the extremity irregularly trilobed and 

 armed with three long spines, the middle one of which is considerably longer than the 

 other two ; two small settu .also spring from near the base of the joint ; the inner 

 produced part of the basal joint is furnished with two spines, the inner one being very 

 long and powerful, the other smaller; all the large spines are plumose (PI. 38. fig. 39). 

 Caudal stylets short, but rather longer than the last abdominal segment (PL 38. fig. 48). 



Sabitat. Pirth of Porth, off St. Monans. 



Remarks. As all the specimens of this Copepod had been in spirit for some time before 

 being identified, we were unable to see the red pigment-sj)ot to which the species owes 

 its name. The form of the animal, together with the divergent setse of the fifth feet, 

 serves to distinguish it when mixed up with any of the other members of the genus. 



EcTiNOSOMA Herdmani *, sp. u. (PI. 36. figs. 16, 44 ; PI. 37. figs. 8, 16, 29, 54 ; 

 PL 38. figs. 7, 25, 33, 47). 



Description. Length "8 mm. (3^- of an inch). Body, seen from the side, fusiform 

 and somewhat similar to Ectinosoma Sarsi, but proportionally narrower ; rostrum 

 prominent. Antennules (PL 36. fig. 44) 6-jointed, moderately slender, the first joint 

 considerably longer than any of the others, as shown by the annexed formula: — 



No. of the joints : 1.2.;^. 4. 5. 6 



Proportional lengths : 13 7 9 6 4 4 ' 



Antenna? somewhat similar to those of Ectinosowa Sarsi, but smaller, and the first two 

 joints of the secondary branch are together nearly equal in length to the third joint 

 (PL 37. fig. 3). 



Mandibles very small, but with a proportionally larger palp than in those of Ectino- 

 soma Sarsi (PL 37. fig. 16). Anterior foot-jaws robust, somewhat similar in form to 

 those of Ectinosoma Sarsi ; the first joint bears only two small marginal processes at the 

 distal end, and the terminal claw-like spines are very long and slender (PL 37- fig. 29). 

 Posterior foot-jaws elongate and slender ; the middle joint is about four times the length 

 of the end one, and is fringed with twelve or fourteen moderately stout hairs (PL 37. 

 fig. 64). 



The first foiu* pairs of swimming-feet somewhat like those of Ectinosoma Sarsi, but 

 much smaller and with the marginal sette plain (PL 38. figs. 7 and 25). 



Pifth pair also similar to those of that species, but the inner portion of the basal joint 

 is less produced ; the secondary joint is shorter, and the ajoical spines are longer and are 

 all of nearly equal length (PL 38. fig. 33). 



Caudal stylets very short and about equal in length to the last abdominal segment 

 (PL 38. fig. 47). 



HaMtat. Pirth of Forth, off St. Monans ; Port Erin, Isle of Man. 



Hemarks. The elongate form of this species, together with the somewhat slender 



* In compliment to Prof. W. A. Herdman, F.R.S. 



