145 



larger projections on the posterior portion. There is a large 

 tubercle above the uropods. The posterior prolongation 

 which roofs the notch is strongly tridentate, and a small 

 median tubercle is just above it. The ridge formed by the 

 upper parts of the epimera of the thorax is more pronounced. 

 There is a conical tubercle on the underside of the peduncle 

 of the uropod. 



A common species. 



Group EuBRANCHiAT^, Hauseu. 



Genus Dynamene, Leach. 



Dynamene ramuscula, n. sp. 



Plate v., figs. 9 to 20. 



The body is strongly convex, rather narrow, covered 

 sparely with long, harsh hairs, which are more numerous on 

 the pleon and uropods. 



The head is a little longer than the first segment of the 

 thorax, convex, and rather abruptly declivous anteriorly. 



The first segment of the thorax is declivous anteriorly, 

 and is longer than either of the four which follow, but not 

 so long as the sixth, which bears two posteriorly projecting 

 processes, which reach nearly as far as the end of the pleon; 

 each of these processes has a slightly sinuous shape and a 

 small branch near the end, which projects downwards. The 

 apices of the epimera are nearly in the same curve, and 

 are without distinct sutural lines marking them off from their 

 respective segments. The seventh segment of the thorax is 

 short, and its small epimera fall short of the preceding ones. 

 The anterior portion of the pleon is only distinctly indicated 

 at the sides, where its anterior angles are nearly right angles. 

 The posterior portion of the pleon is convex, rough, and 

 hairy, having five tubercles; one large median is obscurely 

 cleft apically, two lateral on each side, the more anterior pair 

 larger and nearer the middle; there is also a low tubercle 

 just above the insertion of each uropod. Behind the median 

 tubercle the surface descends abruptly to the posterior notch, 

 which is situated on a conical projection, is a circular fora- 

 men with the inferior slit quite closed for its whole length 

 underneath, and showing a very slight median projection 

 behind at the extremity. 



The eyes are subcircular. 



The antennular peduncle is rather long, projecting dis- 

 tinctly beyond the eyes when raised ; the notch on the first 

 joint, which holds the second, is not deep, and inferiorly 

 there is a small projection. The second joint is rather more 

 than half the length of the first, and projects obtusely beyond 



