318 



One specimen, from Scoresby-Sound (Hekla-Bavn), belongs 

 to the form which W. C.Brøgger has named var. nux^); it is 

 highly ventricous as the var. inflata Leche, but more lengthened. 

 Its measures are: 



Length 16 mm. Height 10*5 mm. Breadth 8"75 mm. 



The shell is frequently more or less covered with a black 

 incrustation. This consists indeed of hardened bottom-material, 

 but its formation and fastening are probably highly supported 

 by the rootlets of a Hydroid (Perigonimus) which grows on 

 the shell. 



At East-Greenland Yoldia arctica has also been taken by 

 the Swedish expeditions. 



First by the Nath or s t-Expedition of 1899 in the fol- 

 lowing places^): 



Scoresby-Sound, Fame Isles 12- 13 fms. Clay 15 specim. 



— — - ca. 5 — Mud 11 — 



— — - 4— 2V2 — Mud 14 — 



72° 1' N. 23° 3' W 17-21— Mud 3 — 



Franz Joseph-Fjord.... ca. 5— IV2 — Mud with sand and algae 11 — 



Cape Benett (73° 26' N.) . . . 5—6 — Sandy mud with algae 1 — 



All these specimens belong to the variety ^90г;(^а>г(^гса Reeve 

 and obtain a length of up to 26"5 mm. (Scoresby- 

 Sound, 12 — 13 fms.), which is the maximum length of 

 the recent individuals hitherto known; thus they very 

 nearly reach the largest known specimens from quaternary de- 

 posits, namely of 27 mm. in the southern Norway and of 

 28'3 mm. in Bohuslän. 



Next by the Ко 1th off-Expedition of 1900 in the following 

 places: 



') Brøgger: Om de senglaciale og postglaciale nivåforandringer i Kri- 

 stianiafeitet, p. 37— 38, Tab. V, Fig. За, b, с. Norges geol. Undersøgelse 

 Nr. 31, 1900-01. 



^) The specimens belong to "Naturhistoriska Riks-Museum» in Stockholm, 

 where I have examined them. 



