26 



rostrum. The abdominal segments have the same dorsal and lateral processes as in S. semi- 

 nudus, but first segment has besides (fig. 2 o) a pair of sublateral, rather short and subcylindrical 

 protuberances a little from its anterior end. The eye-stalks are distinctly shorter than in the 

 Mastigopus shown in fig. 2/, but thicker towards the large, thick, oblique eyes. The antennular 

 peduncles (a l ) without any articulation ; the upper flagellum conspicuously less than half as long 

 as the peduncle, unjointed, and the lower flagellum short though much longer than in 5. semi- 

 ■nudus. The antennal squama (sq.) very narrow, with the distal marginal spine extremely long 

 and originating proportionately considerably behind the end of the squama. The telson (fig. 2q) 

 is short, scarcely twice as long as broad ; its distal part is narrowed and the end strongly 

 emarginate, with a spine from each much produced lateral angle, but no other spines are found 

 on the telson. The exopod of the uropods has its outer margin ciliated in somewhat more than 

 3 / 4 or in almost 4 / 5 °f lis length, and a rather long spine is seen at the end of the naked part. 

 Length without rostrum 3 mm. 



Remarks. — S. oricntalis is so closely allied to S. Edivardsii Kr. that to begin with 

 I had not separated it, but a closer examination gave the result that the petasma differs con- 

 siderably from that in the Atlantic species. As the petasma in the latter form was unknown 

 I thought it nearly necessary to insert a drawing (PI. II, fig. 5 a) for comparison. It is seen 

 that in S. Edwardsii processus ventralis (pv.) is still much smaller and subcylindrical ; the outer 

 branch of lobus armatus (la.) is long and moderately slender, and the long lobus inermis (li.) 

 is longer and only half as thick as in 5. oricntalis. It may be noted that I have inspected 

 the petasma in some specimens of both species and found the differences constant. I have not 

 been able to find other absolutely valid specific differences between the two forms; yet it may 

 be mentioned that S. Edivardsii is frequently somewhat larger than 5. oricntalis, that the two 

 terminal spines on sixth joint of third maxillipeds are subequal in length and frequently in 

 thickness in S. Edwardsii, while in 5. oricntalis they differ generally more conspicuously in 

 size, and in some specimens the spine on the angle is twice as long as the other ; furthermore 

 fourth subjoint of sixth joint in third pair of maxillipeds has in S. Edwardsii a moderately or 

 rather long spine on the lower side near the outer margin, while in S. oricntalis this spine 

 is either quite short or wanting. 



Adult and subadult specimens of S. Edwardsii and .S. oricntalis differ from all other 

 species of group II in having sixth joint of third pair of maxillipeds divided into 6 subjoints, 

 while all the other species hitherto known have only 4 or 5 subjoints, and besides in having 

 the entire outer margin of the exopod of the uropods ciliated, which is not the case in any 

 other species of the genus. 



Distribution. — The Copenhagen Museum possesses male specimens of S. oricntalis 

 from a place a little south-east off South Africa, and from the Chinese Sea at lat. iq°i4'N., 

 long. 11 6° 6' E. (Capt. Andréa). No male of this species has been taken in the Atlantic, while 

 5. Edivardsii has not been discovered in the Indian Ocean or the Pacific. 



