ATLANT. DEEP-SEA EXPED. 1910 VOL. Ill) 



PENEIDES AND STENOPIDES 



25 



The larva; differ from the adults in the following 

 characters: — (1) the eyes are enormus, their greater dia- 

 meter being from 31 to 50 % of the length of the carapace; 

 (2) the relative size of the joints in the antennular ped- 

 uncles shows an approximation towards the proportions 

 found in S. Henseni (see under that species); (3) the 

 percentage of hairfringed edge on the outer uropods is 

 less, beeing from 74 --78 % against about 80% in the 

 adult; (4) the sixt joint of the mxp. 3 is subdivided as in 

 the adult, but carries only spines, something like the 

 abnormal mxp. 3 found in an adult male (fig. 43). 



It may be that Hansen is right in supposing that Masti- 

 gopus tenuis Bate (1888, pi. 65) is identical with Ortmann's 

 S. sargassi. If so, the structure of the uropods and the 

 process on the mxp. 3 indicate its connection with S. pec- 

 tinatus, the said process not being found in S. Henseni. 

 In that case the antennular peduncles must have been in- 

 correctly drawn by Bate. 



S. pectinatus was captured only in the southern 

 part of the area explored by the "Michael Sars", and 

 Ortmann (1893) reports it (and S. Henseni?) from the 

 equatorial region of the Atlantic. 



It seems to live in the upper waterlayers. 



Table of catches 



St. 



Gear 



m. w. 



Number 



Sex, size 



23 



1 sn 



200 



1 



c?5 





34 



y 



400 



1 



$ 4.5, 





42 



y 



300 



3 



? 5, 5. c" 4 





45 



1 sn 



100 



6 



? 4, 4, 4, cT 4, 4, 3 





If 



y 



300 



13 



$ 6, 6, 6, 6, 5, 5, 5, 5, 5, </ 6, 5, 



5,5 



„ 



1 k sn 



1000 



1 



?4 





49 



1 sn 



100 



1 



2.4 





B 



y 



2000 



1 



?6 





,„ 



3 In 



3000 



1 



c?5 





51 



1 sn 



200 



1 



d"6 





B 



V2 sn 



700 



1 



?5 





„ 



y 



300 



3 



? 6, 5, d" 3 





■ 



y 



2000 



1 



?6 





„ 



y 



3000 



1 



?8 





53 



1 sn 



200 



2 



? 7, 7 





56 



x h sn 



500 



1 



? 4 (del) 





62 



1 sn 



200 



1 



d"6 





64 



1 sn 



100 



7 



©3, 2.5, 2,2, 2.2, 2.0, 2.0, 1.8 





„ 



1 sn 



200 



4 



© 2.9, 2.7, 2.7, 2.0 





■ 



y 



300 



5 



©2.7, 2.5. 2.3, 1.3, 0.9 (L = 3) 





„ 



3 A sn 



600 



6 



© 3, 3, 3, 2.2, 2,2, 2.0 





67 



1 sn 



50 



4 



© 2.8, 2.2, 2.0, 1.5 





D 



y 



200 



6 



©2.8, 2.6, 2.5, 2.4, 2.4, 2.3 





64 



y 



1000 



1 



d" 3.5 (L = 10) 





m 



y 



2000 



1 



? 3.5 





67 



y 



1200 



3 



? 5.5, 3.5, J 2.5 





13 



26 





76 





Sergestes Henseni Ortmann. 



Sergia Henseni, Ortmann 1893. 

 Sergestes sargassi, do., (mastigopus). 

 Sergestes Henseni, Hansen 1896 (partim). 

 Sergestes vigilax, Stephensen 1913. 



In describing 5. Henseni it will be convenient to 

 compare it with S. pectinatus. 



The rostrum is of the same shape, but longer than 

 in 5. pectinatus, its length equalling 2 h of the breadth 

 of the cornea. 



The distal joints of the antennular peduncles are 

 nearly of the same length but the first is much longer. 

 In one specimen the following proportion was found: 

 19-10-11, in another: 18—11—13. 



The third pair of maxillipeds are much more slender 

 than in 6". pectinatus, and the sixth joint, which also 

 however, is divided into 5 subjoints, is not provided with 

 a "comb", but carries a crowded armature of long and 

 short spines. (See fig. 44). The relative length of the 

 joints is about as 25 — 36—9 — 9—20 (in the other species 

 as 34—16—16—16—17). 



The hairfringed portion of the outer uropods, which 

 carries sometimes a small tooth, is much shorter than in 

 5. pectinatus, about 60 %. 



Ortmann's figure (1893, pi. 3, fig. 3) is drawn from 

 a specimen of the present species. It is easy to under- 

 stand that Hansen (1896) found this figure "rather defi- 

 cient" because he compared it with a specimen of S. 

 pectinatus (certainly overlooked by Ortmann). The pe- 

 tasma is slender as in 5. pectinatus, but very different 

 in shape (see fig. 45). A singular feature, which I have 

 not observed in other species, is the presence of multiple 

 spines on the process/, somewhat recalling the "morning- 

 stars" of by-gonetimes (se fig. 46). 1 ) 



The larva; are easily separated from those of 5. 

 pectinatus by several characters, viz: (1) the eyes are 

 smaller, their longer diameter (E) compared with the length 

 of the carapace (C) 2 ) being as follows: — 



C— 1-8 2-0 2-3 2-6 3-0 3-1 3-2 3-5 

 E— 0-7 0-65 0-75 0-7 0-7 0-7 075 0-8; 



in Serg. pect: C— 1-5 2-0 2-0 2-2 2-8 

 E— 0-85 1-0 0-8 0-9 09 



(2) the second joint of the antennular peduncles is shorter, 

 though the measurements are rather uncertain owing to 

 the difficulty in securing a horizontal position without 

 injuring the specimens; below the values found: 



') A drawing of the petasma is given by Stephensen 1913 as 

 fig. 6, though he refers his specimens to 5. vigilax. 



-) C is contained a little more than 3 times in the total length. 



SUND — 4 



