of the Fishery Board for Scotland. 243 



basal joint reaches to about the middle of the secondary one (fig. 10). 

 Caudal stylets shorter than the last abdominal segment, and broadly pyri- 

 form. The principal tail setae are as long as the abdomen. 



Male. — Anterior antennae ten-jointed. The fourth joint is narrower than 

 the one that precedes or follows, and is hinged to the fifth ; the sixth, and 

 seventh, are very short, and the joints between the eighth and ninth, and 

 between the ninth and tenth segments, appear to be hinged so that each 

 antenna forms a powerful grasping organ (fig. 3). The inner branches of 

 the third pair extend to the end of the second joint of the outer branches, 

 and is furnished, in addition to the plumose marginal setae, with a ter- 

 minal spine-like appendage (fig. 9). The form of the fifth pair is some- 

 what similar to those of the female, but smaller, and without the very 

 long seta on each of the basal and secondary joints. The sixth pair of 

 appeudages are very broad and short, in fonw * somewhat like the segment 

 of a circle, and furnished with one long and two short setae. 



Habitat. — At Seafield near Leith. Obtained by washing some black 

 sandy mud near low- water mark. 



Remarks. — This large and fine species is readily distinguished from 

 any other British Ameira by the pyriform caudal stylets ; and, on dis- 

 section, by the other characters referred to in the description. 



Ameira exigua* sp. n. (PI. VI. figs. 15, 23.) 



Description. — Female. Length, *47 mm. (x^-rd of an inch). Rostrum 

 prominent. Anterior antennae sparingly setiferous, rather slender, and 

 eight-jointed. The second joint is longer, and the penultimate one shorter 

 than any of the other joints. The proportional lengths of the joints are 

 nearly as shown by the annexed formula : — 



13 ' 16 ' 10 • 7 • 6 • 6 . 3 * 6 • 



1 • 2 • 3 • 4 • 5 * 6 • 7 * 8 ' 



Posterior antennae and mouth organs nearly as in Ameira reflexa. The 

 first pair are moderately stout. The inner branches are of considerable 

 length, but the outer branches are short, and do not reach the end of the 

 first joint of the inner branches. The second joint of the inner branches 

 is small, while the end joint is elongate and slender ; but the second 

 and third joints together are scarcely equal in length to the first 

 joint (fig. 20). In the fourth pair the outer branches are long, and 

 inuer branches short ; the inner branches scarcely extend beyond the 

 end of the second joint of the outer branches (fig. 21). The fifth pair are 

 foliaceous, small. The produced inner portion of the basal joint is broadly 

 sub-conical, and furnished with five terminal and sub-terminal setae ; the 

 second one, from the outside, is considerably longer than any of the others. 

 The secondary joint is broadly ovate, and extends halfway beyond the end 

 of the basal joint, and bears several setae of unequal length round the 

 outer margin and apex, but the inner margin is ciliated (fig. 22). Cauda! 

 stylets shorter than the last abdominal segment, and about as long as 

 broad. The principal seta of each stylet is stout, and longer than the 

 abdomen (fig. 23). 



Habitat. — Off St Monans. Not very common. 



Remarks. — This very small but distinct species somewhat resembles 

 Ameira exilis and Ameira longipes, Boeck. It differs from one in being 

 not only much smaller and comparatively more robust, and in the anterior 

 antennae being eight instead of nine-jointed, but also in the form of the 

 mandible-palp and the structure of the fourth pair of swimming-feet, and 

 from the other by the structure of the mandible-palp and the fifth pair of 

 feet. 



* Exiguus = small. 



