ISOPODS OF NORTH AMERICA. 4:2\) 



This species has throe times been recorded from (xreenland. 

 O. Fabricius recorded it as Oniscus aquaticun. Kr0yer records it as 

 AselluK (/rdnlandlciiis? He says of it/' 



This sj)efies is without doubt the one mentioned by Fabricius under No. 227, and 

 which he himself did not see, although it does not appear to be rare. It approaches 

 so closely our Asellns rnlgarla that it is extremely difiicult to find sufiicient distin- 

 guishing characters in the two. Nor am I entirely t'crtain that I have found such 

 distinguishing characters, and therefore hesitatingly give this animal as a distinct 

 si)ecies, although it seems almost incredible to me that the fresh waters of both 

 Euro])e and (Ireenland should 1)e iidial)ited by theidentical species of Asellns. 



Hansen'' says of AxeUiis g riml andicu>< that it is probably not different 

 from A.se/lns agtiaticas. 



Packard records it from Greenhmd as Asellus (jri'mlandiciis. 



Specimens collected in (rreiMiland, sent to me from the Museum of 

 Comparative Zoology at Harvard University and labeled AscIIuh 

 grdnlandiciis, do not difier in any respect from Asellus aquaticus as 

 described and figured by G. O. Sars. 



Body narrow, elongate, nearly three times as long as wide, 8 nun: 

 8^ nmi., narrower anteriorly and becoming wider posteriori}'. H nmi. 

 is its greatest breadth. 



Head about twice as wide as long, 1 nmi: 2 nnn., with the anterior 

 margin slightly excavate. Lateral margins entire, with a small lobe 

 on either side near the posterior margin. Eyes small, distinct, com- 

 posed of only three or four ocelli and situated close to the lateral 

 margin, halfway between the anterior and posterior margins. The 

 first pair of antennte have the basal article large and dilated; the second 

 article is half as wide and but little longer; the third article is two- 

 thirds the length of the second. The fiagelkmi is composed of eleven 

 articles and extends to the end of the peduncle of the second pair of 

 antennie. The second pair of antennje have the first two articles short 

 and subequal; the third is one and a half times longer than the second; 

 the fourth article is nearlj- as long as the first three taken together; 

 the fifth is one and two-thirds times as long as the fourth. The flagel- 

 lum is composed of about fortj^-four articles, and extends to the pos- 

 terior margin of the fifth thoracic segment. It measurt\s (i mm. in 

 length. 



The first segment of the thoi-ax has the epimera conspicuous and 

 situated in the antero-lateral corners. In the second and third seg- 

 ments they are small and almost inconspicuous lobes situated at the 

 antero-lateral corners of the segments. In the fourth segment they 

 are small and inconspicuous and situated just below the antero-lateral 



" Kongelige danske videnskabernes Selskabs naturvidcnskabelige og mathematiske 

 Afhandlinger, VII, ISIW, p. :^18. 



(' Videnskabelige ]Meddelelser fra lU'ii naturhistoriske Foreniiig i KJ0l)t'nliavn, 

 1SS7-8S, p. 190. 



