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Show 1896.] OF THE GENUS SERGESTES. 947 examined the type specimen and must declare it to be a large female of S. arcticus, Kr. Sp. Bate has iu all established 24 new species of Sergestes, of which but 3, S. prehensilis, Bate, S. japonlcus, Bate, and S. krdgeri, Bate (all briefly characterized in 1881), are decidedly adults. Of the other species,/^, longicollus, Bate (p. 421, pl. lxxvii. fig. 1), at least has almost arrived at the shape of the adult, but it is, as pointed out by Ortmann, synonymous with S. tenuiremis, Kr. It is impossible to m e to form any idea of S. profundus, Bate (p. 428); Bate's specimens were very much mutilated. The other 19 species and Sciacaris telsonls, Bate (p. 438, pl. lxxviii. fig. 1), are all MasHgopus-iorms in very different stages of development.-When Bate (p. 393, pl. lxviii.) describes and figures trl.4 and trl.5 in S. atlanticus, M.-Edw., as very short, this must, in m y opinion, arise from an anomaly or from some other reason of no value, if the described and figured specimen really belongs to this species, for I a m not convinced that all the specimens from tbe localities enumerated (p. 390) belong to S. atlanticus. H e states that a specimen, 50 m m . in length, was taken " off Japan ; depth 345 fathoms," and that 3 specimens, 43 m m . long, were trawled " south of Australia ; depth 2150 fathoms." These 4 specimens at least must be re-examined, as among some hundred specimens I have not found one exceeding 30 mm., and the localities also make the determination somewhat doubtful. The specimens of S. edwardsl, Kr. (Bate, p. 403), must also be re-examined with the aid of m y descriptions of hitherto not recognized allied species. 8. mollis, Smith, established by that author in 1884 (Rep. Comm. Fish and Fisheries, pt. x. p. 419), I consider to be identical with S. japonlcus, Bate (described 1881), with which it agrees in the smallness of the eyes, the relative length and thickness of the joints in the antenn. ped., the shape of the squama, the soft aud membranous integuments, and the number and the feeble development of tbe posterior branchiae. S. magnificus, Chun, established in 1888 (p. 33, Taf. iv. fig. 4 u. 5), is, according to m y examination of one of the type specimens, identical with S. arcticus, Kr. Kroyer also has stated that the flagellum of tbe antennaa surpasses the total length of the animal about 3 times.-S. sanguineus, Chun, established in 1889 (p. 538, Taf. iii. fig. 1), is, as stated above, identical with 8. obesus, Kr., and will be discussed later on under Petalidium. In 1891 Wood-Mason (Ann. & Mag. Nat, Hist. 6th ser. vol. vm. p. 354) established 8. rubroguttatus, W.-M., a species closely allied to 8. arcticus, Kr., but the differences in the ext. br. of urp. pointed out by the author are certainly valid specific characters. For the rest, I believe that it may be possible to detect more characters. Perhaps the species is identical with S. kroyeri, Bate, established 1881, but both species being insufficiently Ascribed, Isp eOccfaien snt.oh te sseptetcliee st ehset aqbuleissthieodn r,bt ya nWd. tFhaexroefno rien 1m8u9s3t, „Ss .u7 p hpa,oh.ra t,- pF,b aotxh. |