]J11IAN(; TILL K. SV. VET.-AKAI). JIANDL. HAND 20. AFD. IV. Nid 1-*. Öl 



The greatest depth from whicli it was brought iip by 

 meaii8 of the »buUdog-machine» was estimated at 2600 fathoms, 

 and that great depth has since that time been marked on all 

 bathyiuetrical maps of the Aretic Ocean as the Swedish 

 depth». The Swedish Aretic Expedition 1.S98 is the first which 

 has proved by modern and exact methods that there is an 

 exaggeration in this point. No greater depth than 3200 m. 

 was ever sounded in this tract of the ocean. 



Diaatylis polaris seems to belong exclusively to the great 

 depths in the North Atlantic and Aretic Oceans. It was ob- 

 tained during the 'Lightning' Expedition at lat. HO ol' N., 

 long. 9 18' W., during the 'Porcupine' Expedition at lat, 

 48 50' N., long. 11° 9' W., during the 'Challenger' Expedition 

 at lat. 41' 14' N., long. 65 45' W., off Nova Scotia, and during 

 the Norwegian North Atlantic Expedition at nine different 

 stations, all belonging to the cold area, and in depths reach- 

 ing lo3o fathoms. It was also obtained during the Danish 

 Ingolf Expedition (Hansen). 



It has been impossible for me to distinguish Diastylis 

 polaris and D. stijgia. In the presence of obliquely trans- 

 verse rugee on the carapace my specimens agree perfectly 

 with D. poluris as described and iigured by Särs. but differ 

 from this, and come nearer to D. stygia, in having the spi- 

 nules on the carapace much stronger than in Särs' figures of 

 his D. polaris. The spinules along the antero-lateral borders 

 of the carapace, when seen from above, are even more pro- 

 nounced than in Särs' 1). stygia. I could count 12 — 15 such 

 spines on either side, and even more in a young male. The 

 segments of the tail are, except in a young specimen of the 

 length of about 6 mm., on the upper surface covered with 

 small scattered spinules, like those on the carapace, and the 

 posterior margin is finely, but distinctly denticulated. 



Length of a young male 12 mm. 



breadth ^ . 2,5 /^ 



length ■' >/ » female 11 » 



breadth > ^ v 2,5 » 



