ATLANT. DEEP-SEA EXPED. 1910. VOL. III.] 



PENEIDES AND STENOPIDES. 



and Norse Expeditions, on the Norwegian Coast as far 

 north as in the Trondhjem-fiord. In May 1911 it was 

 taken in the Sogne-fiord along with Paslphcea principalis 

 and P. multidentata (Sund 1913). Generally it may be 

 stated that Sergestes arcticus in the Northern Atlantic 

 has nearly the same distribution as the genus Pasiphcea. 



Table of catches. (Hauls dujing night marked * ) 



St. 



Gear 



m. w. 



Number 



Sex, stze 



10 



y 



300 



1 



? 11 





„ 



? 



? 



1 



$ 12 





19 



4 In 



900 



5 



$ 12. 11, 10, ©6, 5 





23* 



y 



400 



1 



©7 





42* 



1 sn 



200 



1 



?8 





53* 



y 



1600 



1 



©5 





62* 



1 sn 







2 



©5, 4 





n -1 ' 



y 



1000 



4 



© 6, 6, 6, 5 





64 



1 sn 



100 





1 mast. 





66 



3 /i sn 



1500 



9 



© 7, 7, 7, 7, 6. 6, 6, 6, 4, 





n 



s /i sn 



1000 



2 



©6, 6 





„ 



y 



1500 



4 



© 7, 7, 6, 6, 





70 



3 A sn 



70 



3 



© 8, 7, 5 





o 



y 



1700 



19 



? 19, 18, 18, 17, 17, 17, 16, 

 cT 14, 13, 13, 13, 13, 13, 12, 



©7 



16, 15, 

 12, 12, 



80 



y 



1000 



5 



? 15, 14, © 5, 5, 5 







3 A sn 



1500 



1 



©6 





n 



y 



2000 



1 



? 16 





t» 



3 In 



3000 



2 



? 18, 16 





81 



1 sn 



100 



7 



4 mast., 3 acanthosoma 







3 A sn 



600 



1 



©3 





82 



1 sn 



100 



20 



5 mast., 15 acanthosoma 





» 



1 sn 



200 



13 



mastigopus 





84 



3 /i sn 



600 



1 



©4 







3 /t sn 



1500 



2 



©5, 4 





87 



y 



1000 



12 



© 8, 7, 7, 7, 7, 6, 6, 6, 5, 5, 



5, 5 



88 



1 sn 



100 



2 



©8, 7 





„ 



y 



300 



2 



©7, 7 





„ 



y 



1000 



4 



©9, 9, 6, 6 





90 



3 A sn 



600 



2 



©5, 4 







y 



1000 



3 



©9, 9, 6, 6 





92* 



1 sn 



100 



2 



©6, 4 





* 



y 



300 



2 



©9, 9 





* 



y 



2000 



1 



©4 





94 



3 In 



2000 



1 



? 14 





98 



1 sn 



200 



2 



©5, 5 





„ 



y 



600 



3 



© 9, 8, 7 





„ 



y 



1000 



5 



©9, 9, 6, 6, 6 





„ 



3 /4 sn 



1450 



1 



©6 





n 



3 In 



1500 



10 



$ 19, 16, 15, 15, 14, 13, ©9, 



8, 7, 7 



101 



y 



600 



4 



© 7, 5, 5, 5 





n 



3 h sn 



1500 



2 



©6, 4 





* 



y 



2000 



2 



? 17, ©5 





•n 



3 In 



2500 



3 



? 15, 14, 13 





102* 



y 



600 



3 



© 6, 3, 3 





n 



3 In 



1500 



1 



cM6 





21 



45 





170 



cT 10, ? 27, © 133 



Sergestes corniculum (Kroyer). 



5. corniculum, Kroyer 1860 (larva). 



5. corniculum, Bate 1888 (do.) 



S. corniculum, Hansen 1896 (do.) 



S, corniculum, Hansen 1903 (do.) 

 ? S. rubroguttatus, Lo Bianco 1904 (adult). 

 ? S. rubroguttatus, Pesta 1913 (adult). 



5. vigilax, Stephensen 1913 (do.) 



Young specimens of this species were described by 

 Kroyer in 1860, and later on Hansen (1896) gave further 

 particulars, and added a description of stage still younger 

 than that described by Kroyer. The adult was captured 

 in the Mediterranean by the "Puritan" and a drawing 

 of it was published by Lo Bianco (1904). — It was subse- 

 quently examined by Pesta and Stephensen, who gave 

 drawings of the petasma. I am not quite sure that the 

 Mediterranean species is identical with the Atlantic one; 

 there seems to be a very slight difference in the form of 

 the petasma but it may be accidental. 



This fine large species is closely related to S. rubro- 

 guttatus, Wood Mason. 



That I am right in referring the adult form to the species 

 described from larval specimens by Kroyer is proved by 

 a study of the outer maxillipeds. Fig. 6 shows the 6th 

 joint in an adult and in a mastigopus; in the last-named 

 the four distal subjoints are not yet distinctly divided 

 from each other, and in neither can the subdivision of 

 the two long proximal subjoints, mentioned by Hansen, 

 be seen with certainty. 



The branchial apparatus agrees closely with the de- 

 scription given by Hansen (1896, p. 957). In the adult 

 the relative lengths of the four posterior branchiae (those 

 above the 3rd and 4th pereiopods) are about as follows: 

 9—3—6—4. 



The mxp. 3 do not differ very much from the pereiopods, 

 an only the proximal two-fifths of the external uropods 

 are devoid of setae on the outer edge. Nor does this 

 edge carry any spine (see fig. 7). The rostrum (PI. II, 

 fig. 1) is small, ending in a blunt tooth, directed for- 

 ward. Ocular and hepatic spines present. Cervical groove 

 distinct; so are also the branchiocardiac groove and ridge, 

 which run backwards to the edge of the carapace. The 

 pleon is smooth, the pleurae rounded, and the sixth somite 

 is very powerful, being nearly twice as long and one-half 

 deeper than the fifth. 



The integument is transparent (but not soft) save 

 for some red spots on the fore part of the body (see 

 fig. 8). — The pleon also probably carries such patches* 

 but they are not visible in the preserved material. The 

 stomach is of a bright red colour, clearly visible through 

 the transparent body. S. rubroguttatus Wood-Mason is 

 the only other species of this type of colouring. 



sund — 2 



