1896.] OF 5CHE QBNUS SBEGESXES. 949 



Gboup I. 



Mxp? at most hut little lonr/er, sometimes shorter tJian trU, its first 

 joint rarely, tJie second-fourth joints never ohviously incrassaled in 

 proportion to the joints in trl.^, its two distal joints with numerous 

 bristles aloug both margins. (In the Mastigopus, S. longispinus, 

 Bate, the first joint is somewhat incrassated, the fifth joint with 

 but few bristles, the sixth only with setse along the one margin.) 



A. On tlie ext. br. of urp. the ciliated part never occupies the 

 half of the exterior margin. 

 a. The body very long and slender ; the distance between 

 the eye-stalks and the mandibles very long. 

 S. tenuiremis, Kr., H. J. H. 

 S.jwiceus, Bate. 

 S, longicollus. Bate. 

 h. The body shorter and less slender ; the distance between 

 the eye-stalks and the mandibles not very long. 

 , The first joint in the antenn. ped. about as long as or 

 shorter than the third. 



' *S. atlanticus, M.-Edw. (S. frisii, Kr., 

 S. pacijicus, Stimps.). 

 S. ancylops, Kr. 

 S. ovatoculus. Bate. 



{*S. cor 71 lit us, Kr. 

 S. longispinus. Bate. 

 *S. i n u s, Faxon.' 

 fS. The first joint in the antenn. ped. considerably or 

 much longer than the third. 



1. The second and third joints in the antenn. ped. stout. 



*S. robustus, Smith. 

 *S.japonicus, Bate (S. mollis, Smith). 

 *S. bisulcatus, Wood-Mas. (S. phorcus, 

 Faxon, olim). 



2. The second and especially the third joint in the 



antenn. ped. slender. (The arcticus-gvow^.) 



{*S. arcticus, Kr. {&. meyeri, Metzger, 

 S. magnijicus, Chun). 

 S. rinJcii, Kr., vix Bate. 

 S. di^similis. Bate. 

 S. mediterraneus, n. sp. 

 *S. prehensilis. Bate. 

 *S. kr oy eri. Bate. 



{S. dorsospinalis. Bate. 

 S. laterodentatus, Bate. 

 ;Si. nasidentatus. Bate. 

 (S. rinkii. Bate, vix Kr.) 

 S. Iceviventralis, Bate. 

 *S. rubroguitatus, "Wood-Mas . 



' According to the description this species must belong to this subdiviBion , 

 but it does not agree with the figure {op. cit. pi. li. fig. 2), which shows the first 

 joint a little longer thou the third. 



