OSCAR SUND 



[REP. OF THE "MICHAEL" SARS NORTH 



The antennular peduncles are of the same type as 

 those of S. robustiis, though the 2nd joint is relatively 

 slightly longer, resembling that of S. phorcus (see fig. 24). 



The scaphocerite (fig. 24) differs from that of S. phorcus, 

 the outer edge being less curved, and the inner being 

 slightly concave in its outer two-thirds. Its under side 

 carries more feather bristles than in any other Sergestes 

 known to me. These bristles are sparsely implanted in 

 a longitudinal bed along the middle of the scaphocerite> 

 and their length equals about one-third of the breadth 

 of the appendage. The scaphocerite carries a row of 

 9 — 10 luminous (?) patches. 



The fourth pair of pereiopods differs from those 

 both of S. phorcus and of S. bisulcatus in having the 

 two last joints broader, the greatest breadth of the pen- 

 ultimate joint being more than one-fourth of its length. 



The exopodite of the outer uropod is shown in fig. 

 25. The spine is situated slightly more than two-thirds 

 from the base (in S. phorcus slightly less), the breadth 

 is contained about 472 times in the length (in S. phorcus 

 about 5 times). The general form recalls that found in 

 S. sptendens. In S. bisulcatus the uropod is of quite 

 another type. 



The telson has dorsally a broad shallow groove, the 

 limits of which bend slightly together just before the 

 middle and form the dorsolateral edges of the telson in 

 its posterior part. 



Male. The only male (from st. 51) differs from the 

 females in the larger size of its eyes, a sexual difference 

 also found in S. robustus. The grooves and keels on the 

 carapace are less distinct, and the integument on the 

 whole is stiffer than in the females, perhaps depending 

 upon difference in time since the last moult. 



The petasma (fig. 26) possesses one process more 

 (h) than in that of S. robustus, thus strikingly resembling 

 the petasma of S. phorcus, from which it differs however 

 in the following points: — (1) the process b ends in a 

 strongly curved hook, (2) the process e is much shorter. 

 (Compare the drawing in Faxon, 1895, pi. LII). 



Sergestes grandls, like S. phorcus, has been captured 

 on a few occasions only, and apparently does not in- 

 habit the superficial waterlayers. Some of the specimens 

 showed traces of red pigment (S. phorcus is reported to 

 be deep red). During the "Michael Sars" expedition it 

 was taken as follows: — 



St. 34, y, 400 m. wire, one, ? 10 



49, 4 In, 3000 - 



51, 3 In, 4000 - 



52, y, 600 - 



. y, 1200 - 



one, ? 12 



one, </ 20 



one, ? 17 



two, ? 18, 12-5 



Stebbing (1908) also describes a "S. bisulcatus" from 

 S. Africa taken i 250 -300 fathoms, 29 miles E b N. of Cape 

 Point. He says that his specimens "agree so closely with 

 Faxon's description that it would be rash to base a 

 specific separation on the one or two minute differences 

 which I have noticed". A glance of his figure however 

 shows at once that his species has nothing to do with 

 Faxon's. The form of the carapace is different in many 

 respects, and it is not easy to understand how Stebbing 

 could arrive at such a conclusion. 



Neither is his species identical with that described 

 here as S. splendens, with which it seems to have the 

 nearest relations, as mentioned under that species. 



Sergestes tropicus n. sp. 



This species shares with S. phorcus Faxon (described 

 as 5. blsculatus, Faxon 1895) 1 ), and S. Kroyerl Bates, 

 and 5. gardlnerl Kemp, the character of having a con- 

 spicuous tubercle on the eyestalk. Faxon does not mention 

 it in the text but it is seen in his figure. S. tropicus 

 is easily distinguished from S. phorcus by the form of 

 the petasma, compare fig. 27 with Faxon's figure (1895, 

 pi. 52, fig. 1 h), and from S. Kroyerl by the form of the 

 rostrum (compare fig. 28 and fig. 29, the last being taken 

 from Hansen 1903). 



The uropods (fig. 33) are narrower (breadth con- 

 tained 472 — 5 times in length) than _ in 5. Kroyerl, the 

 uropods of which are "at most four times longer than 

 broad". 



From S. gardlnerl Kemp the present species is easily 

 distinguished by the form of the petasma, of which Kemp 

 (1913) gives an excellent drawing (pi. 7, fig. 4). 



The third pair of maxillipeds are considerably shorter 

 than the third periopods, the length of the joints (begin- 

 ning with the second) being in a d" 21 from st. 64: 

 6-5, 6-0, 7-0, 6-7, 6-0 mm. The fifth joint is subdivided 

 into three subjoints the relative length of which are as 

 36 : 1 1 : 20. The sixth joint is subdivided into 8 subjoints, 

 the relative length of which are as 17:20:14:13:13: 

 15: 14: 13. 



The scaphocerite, which does not reach beyond the 

 middle of the third joint of the antennular peduncles 2 ) 



The telson ends in a point and carries three pairs of 

 spines along the dorsolateral edges and three other pairs 

 is broad and the lamellar portion is much in advance 

 of the triangular tooth. (See fig 30 and 31 where also 

 the ocular tubercle is visible). 



*) As regards the name 5. bisulcatus, see under S. grandis. 

 2 ) According to Bate (1888, p. 388) it reaches, in 5. KrOyeri 

 to the tip of the antennular peduncles. 



