g4 CRUSTACEA MALACOSTRACA. III. 



was correct, because Sars has figured the female with the distance between the keels still shorter than 

 in an)' of my specimens, and the operculum less cut off posteriorly, Prof. Sars, on my request, kindly 

 sent me some fine females, but these have the frontal emargination as broad as, or even a little broader 

 than, in my specimens from Stat. 32, thus differing in this feature much from his figure, and the 

 squama is in these Norwegian specimens much longer (fig. 4 f) than the diameter of third peduncular 

 joint, longer than in any of the "Ingolf specimens. After careful examination of the females to hand 

 from various places I think that the)- all belong to N. oblongus G. O. S. That the animal described 

 and figured by Sars as the male is in reality a not adult female of a very different form, A r . crassipcs 

 11. sp., is proved on p. 87 — 88. 



Occurrence. Taken by the "Ingolf at three stations in the warm area. 



Davis Strait: Stat. 32: Lat. 66°35' N., Long. 56°38' W., 318 fath., temp. 3-9°; 8 spec. (?). 



West of Iceland: Stat. 98: Lat. 65°38' N., Long. 26°27' W., 138 fath., temp. 5-9°; 1 spec, (young ^). 



South-West of Iceland: Stat. 78: Lat. 6o°37' N., Long. 27°52' W., 799 fath., temp. 4-5°; 14 spec. 



(3 <?. " ?)■ 

 Distribution. Sars established N. oblongus on specimens captured "off the Lofoten Islands, 



at Skraaven, in depths ranging from 120 to 250 fathoms". The specimens he sent to me have been 



taken after the publication of his work quoted at Korshavn, near Cape Lindesnaes (south end of Norway). 



56. Nannoniscus arcticus n. sp. 

 (PL VIII, figs. 5 a- 5 d). 



Female. So closely allied to N. oblongus, that it may be sufficient to deal with features deviat- 

 ing from what is found in that species. — The head (fig. 5 a) about four and a half times as broad as 

 the distance between the anterior ends of the keels limiting the front area; the anterior margin between 

 these keels is deeply concave. — The antennulse a little longer than in N. oblongus; first joint distinctly 

 shorter than the second (fig. 5 b); the process from fourth joint reaches considerably beyond the middle 

 of the pyriform vesicle. — Autennal squama marked off and considerably shorter than the diameter 

 of third peduncular joint. 



The two posterior thoracic segments with the median part of the ventral side strongly vaulted 

 (fig. 5 c). — The operculum, which is a little longer than broad, has the posterior margin considerably 

 convex, and the ventral process is short and placed somewhat near the base. — The uropods have 

 the peduncles short and broad, the endopod considerably thicker, but only somewhat shorter, than the 

 exopod, which is longer than in the two preceding species. 



Length of the best specimen, a female without marsupium, 2'8 mm. 



Remarks. A", arcticus is distinctly larger than N. oblongus, and among the differences men- 

 tioned those drawn from the distance between the front end of the cephalic keels and the length of 

 the squama are easily observed and are certainly valid specific characters. While A r . oblongus is known 

 only from the warm area, A. arcticus is a cold water form. 



Occurrence. Taken bv the "Ingolf at a single station in the cold area. 



