I'kl M U I \ \l \I.KitsTK\CA. III. 5 



Tatt, fairvdiif C.nmaldii ' Dollf. and n *\>.. /Jo/Am Htttallica Rose, the larval stages of Sytcrnus 



Harp, and of Epicaridca. The species of the sub-family .ginac are either living on fishes or 



are found at the bottom, frequently in depths of several hundred fathoms, but probably they frequently 



in alxmt looking for a host, while their ovigerous females take no food and live only on the bottom. 



When speaking of bathymetrical distribution all these animals living either constantly pelagically or 



during periods of their life as parasites may be put aside. 



Nearly all other Isopoda dealt with in the present paper are living during their whole life either 

 <>n or near the bottom. G. O. Sars has collected large numbers of specimens of the genera Rurycopr, 

 llyarathna and Munnof*is\ he has described their methods of walking and swimming, but according 

 to his statements one must conclude that they constantly live at or near the bottom. I do not know 

 a single instance of any species of these genera, excepting Ear. Murrayi Walk., having been taken in 

 any instrument not sunk to or very near to the bottom. It may be possible that some species of the 

 genera Dfsmosoma G. O. Sars and Natinoniscus G. O. Sars sometimes may raise from the bottom and 

 swim about, but judging from the fact that only a single specimen of these genera, vix_ Desmosoma 

 chrlatum Steph., has been recorded in the literature as taken pelagically and even at a station 

 between Elba and Corsica, together with 3 species of Apscudcs otherwise never before taken in this 

 way this mode of living must be extremely exceptional, as both genera comprise numerous species. 

 And many Isopoda, f. instance the species of the /scAaomi-sus-ffroup, are certainly quite unable to swim. 



A restricted number of Isopoda live either near the shore (/erra) or iu depths from very few to 

 50 or sometimes about a hundred fathoms (/anira tricornis Kr., some species of Afunna, most species 

 of Idothra\. /anira maculosa Leach is most remarkable, as it has been taken in most different depths, 

 from a few down to more than a thousand fathoms, and the specimens inhabiting rather low water 

 differ, as is shown later on, markedly from those captured in the deep sea. 



The great majority of the Isopoda from our area are bottom animals living in rather consider- 

 able or great depths. The two richest places are the two "Ingolf" stations 78 and 36, both in the 

 warm area. At Stat 78, 799 fathoms, an enormous quantity of bottom material, especially sponges, 

 was hauled up, and 22 species of Isopoda were found ; at Stat 36, 1435 fathoms, the bottom material 

 did not fill a liter in a sifted condition, but it contained 18 bottom species, and two certainly bathy- 

 pelagic species were found in the meshes of the trawl. A number of bottom forms were also procured 

 at two other of the deepest stations in the warm area, viz. at Stat. 24, 1199 fathoms, 15 species, and 8 

 species at Stat. 38, 1870 fathoms. With very few exceptions the forms taken at these four stations 

 belong to the Asellota, and as to this sub-order we arrive at a similar result as that pointed out in 

 my report on the "Ingoir Tanaidacea on the rich family Tauaidae, that the richest harvest was yielded 

 by some of the deepest stations south and west of southern Greenland. The only other rich places 

 are the above-named Stat 78, 799 fathoms, far south-west of Iceland, and Stat 25, 582 fathoms,* in 

 Davis Strait, where 16 species, 12 among them Asellota, were gathered. At the three stations 24, 36 

 and 38, with depths from about 1200 to 1870 fathoms, together with Stat 78, were taken in all 33 new 

 species of the Asellota. 



Of the total number of Isopoda only 17 species have been taken exclusively in temperatures 

 below zero, and 15 of these in at least 293 fathoms, and generally in greater depths, thus exclusively 



