1896.] OE THB GENUS SEBGE3TES. 947 



examined the type specimen and must declare it to be a large 

 female of S. arcticus, Kr. Sp. Bate has in all established 24 new 

 species of Sergestes, of which but 3, S. preliensilis, Bate, 

 S. japonicus, Bate, and ;{?. Jcroi/eri, Bate (all briefly characterized in 

 1881), are decidedly adults. Of the other species, (S'. longicolliis. Bate 

 (p. 421, pi. Ixxvii. fig. 1), at least has almost arrived at the shape 

 of the adult, but it is, as pointed out by Ortmann, synonj'mous 

 with S. fenuiremis, Kr. It is impossible to me to form auy idea 

 of S. jirofundus, Bate (p. 428) ; Bate's specimens were very much 

 mutilated. The other 19 sjiecies and Sciacaris telsonis, Bate 

 (p. 438, pi. Ix.wiii. fig. 1), are all Mastu/ojms'tovms in very difEerent 

 stages of development. — When Bate (p. 393, pi. Ixviii.) describes 

 and figures trl.' and trl.' in ^S*. allantieus, M.-Edw., as very short, 

 this must, iu my 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 am not convinced that all the specimens 

 from the localities enumerated (p. 390) belong to S. atlanticus. He 

 states that a specimen, 50 mm. in length, was taken "off Japan ; 

 depth 34r) fathoms," and tliat 3 sjjocimons, 43 mm. long, were 

 trawled " soutli 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 determinatiou somewhat doubtful. The 

 specimens of S. edwardsi, Kr. (Bate, p. 403), must also be 

 re-examined with the aid of my descriptions of hitherto not 

 recognized allied species. 



S. mollis, Smith, established by that author in 1884 (Eep. Comm. 

 Fish and Fisheries, pt. x. p. 419), I consider to be identical with 

 i>. japoniciis. Bate (described 1881), with which it agrees in the 

 smalluess of the eyes, the relative length and thickness of the joints 

 in the antenn. ped., the shape of the squama, the soft and 

 membranous integuments, and the number aftd the feeble 

 development of the posterior branchise. 



S. magnificus, Chun, established in 1888 (p. 33, Taf. iv. fig. 4 u. 

 5), is, according to my examination of one of the type specimens, 

 identical with S. arcticus, Kr. Kroyer also has stated that the 

 flagellum of the antenna) 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 S. ohesus, Kr., 

 and will be discussed later on under Petalidium. 



In 1891 Wood-Mason (Ann. & Mag. Nat. Hist. 6th ser. vol. viii. 

 p. 354) established S. ruhroguttatus, W.-M., a species closely allied 

 to S. 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. krogeri. Bate, 

 established 1881, but both species being insufficiently described, 

 I cannot settle the question, and therefore must support both 

 species. 



Of the species established by W. Faxon in 1893, S. lialia, Fax. 



