1896.] OF THE GENUS SEKGESTES. 961 



the one margia furnished with extremely short spines or almost 

 naked, while the other margin of the sixth joint and at least of the 

 distal half of the fifth joint is armed with rather numerous spines, 

 some of which are very long and rather robust. The differences in 

 the armature, especially of the sixth joint, yield very good characters 

 for the species. (The distal part of the fifth joint is most frequently 

 cut off by a secondary articulation.) The eves are middle-sized, 

 the supraocular and hepatic spines well developed. In the antenn. 

 ped. the first joint is very little longer to somewhat shorter than 

 the third joint, which is slender and obviously longer than the 

 second. On the third joint of trl.' and trl.^ the processes represented 

 by Kriiyer in S. edwarchi (tab. iv. fig. 9 / and 9 _f/) are well 

 developed. The brancliial formula as in S. allanticus, M.-Edw. 

 (see above) ; the briinchise above the trunk-legs are very long, above 

 trl.' one branchia and a lamella ; trl.'' 2 brauchiaB, the first of which 

 is about as long as the preceding, the second somewhat shorter and 

 only half as broad, but yet very well developed. The exterior 

 margin of the ext. br. of urp. without any spine or tooth at the 

 {)roximal end of the ciliated part. 



S. edwarchi, Kr. — Krdyer in his representation ( p. 240, tab. iv. 

 fig. 9, a-k) mentions a variety with longer rostrum, but this 

 belongs to another species, viz. S. penerinki. Bate, H. J. II. The 

 species is easily distinguished from all the other species by the 

 cliaracter given in my tabular view : that the ext or. of urp. has 

 the exterior margin ciliated along its whole length — and besides 

 by the following features in the structure of mxp.' The sivth 

 joint of this pair is divided into 4 stihjoints about equal in lenr/ih, 

 and each of the 2 distal stihjoints is rather or very distinctly divided 

 into 2 suhjoints, thus in all 6 subjoints; the joint ends luith 2 sjniies 

 of equal or different length, but at least the one is very long ; next 

 its interior margin is furnished with 35-38 spines of very different 

 lengths (and the apical spine on the first, second, and fourth of the 

 6 subjoints is exceedingly long) ; besides a very long spine is present 

 on the same three subjoints on the one side near the exterior margin. 

 The fifth joint of mxp.' also presents some characters, which, 

 however, are omitted. The rostrum is shorter than in tlie other 

 species of the group, laterally compressed, and seen from the side 

 more or- less plainly forming an oblique triangle. — Length 14- 

 21-5 mm. 



I have seen specimens from the Atlantic northward to lat. 20° N. 

 (the larvffi to lat. 23° 31' N.), from the Indian Ocean, and passing 

 towards the Pacific to Djilolo Isl. (c. lat. 1° N., long. 127° 5' E.). 



The three, or perhaps four, next species are easily separated from 

 S. edivardsi, Kr., by sevei'al characters. On the ext. br. of urp. at 

 least c. ^ of the exterior margin is naked. In mxp.^ the sLvth joint 

 is divided into hut 4 suhjoints very unequal in length, the third 

 being but half as long as the second ; the joint ends with but one 

 spine, which is very long, and the interior margin of the joint is 

 armed with but 15-25 spines, and no spine exists on the side of 

 any of the subjoints near the exterior margin. 



62* 



