BELONGING TO THE GENERA BEADYA AND ECTINOSOMA. 439 



foot-jaws; it also wants the prominent rostrum of the typical Ect'mosoma; but these 

 differences are so small as, in our opinion, to be of no more than specific value. The 

 elongate antennules of this species cannot be considered to l)e of any more than specific 

 importance, as those of some of the other species now described are also of considerable 

 length. 



EcTiNOSOMA LONGICORNE, sp. n. (PL 36. figs. 23 and 38; PL 37. figs. 7, 25, 33, M; 

 PL 38. figs. G, 28, 29, 50.) 



Description. Length '6 mm. (-^-^ of an inch). Body moderately robust ; seen from 

 the side, the dorsum tapers gradually from the fii-st cephalothoracic segment to the 

 extremity of the abdomen, while the anterior end is boldly rounded to where it merges 

 in the somewhat prominent rostrum (PL 36. fig. 23). 



Antennules (PL 36. fig. 381 elongate, slender, and G-jointed ; the first joint is consi- 

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



No. of the joints : 1.2.3 .4.5.6 _ 



Proportional lengths : 18 "8 'll 5 5 9 ' 



econdary liranches of the antennae very slender, 3-jointed, rather longer than the 

 second joint of the primary branches ; the first and third joints are subequal in length, 

 but the second is very small (PL 37. fig. 7). 



Mandibles armed with a few large apical teeth and a short marginal spine ; the basal 

 joint of the palp is provided with a few terminal setse, and both of the one-jointed 

 branches are comparatively Avell developed, but the apical is about twice the length 

 of the marginal branch (PL 37. fig. 25). Anterior foot-jaws stout, somewhat similar 

 to those of Ectinosoma Sarsi, but the seta3 of the marginal processes on the first joint 

 Are not plumose (PL 37. fig. 33). 



The posterior foot-jaws also resemble those of Ectinosoma Sarsi, but are more slender 

 (PL 37. fig. 41). 



First four pairs of swimming-feet slender and furnished -with plain marginal setse 

 .(PL 38. figs. G and 28). 



The fifth pau" are small, and somewhat resemble those of Ectinosoma pi/gmcetim ; but 

 the apical setae are not fusiform, and the middle seta of the secondary joint is consider- 

 ably longer than the one on either side (PL 38. fig. 29). Caudal stylets short, being 

 about equal in length to the last abdominal segment (PL 38. fig. 50). 



Habitat. Pirth of Forth, off St. Monans. 



liemarJis. The elongate antennules, the slender 3-jointed secondary branches of 

 the antennae, and the slender foot-jaws readily rlistinguish this from other species of 

 Ectinosoma. We do not know of its occurrence beyond the Forth area. 



Ectinosoma tenuireme, sp. n. (PL 36. fig. 33 ; PL 37. figs. 8, 27, 3G, 46 ; PL 38. 

 figs. 1, 24, 40, 49.) 



Lescription. Eesembling Ectinosoma gracile in general appearance. 



Antennules 7-jointed, and somewhat like those of Ectinosoma gracile, but more 

 elongate, and the penultimate joint is nearly equal in length to the first, and aboUt 



