KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 48. N:0 1. 



65 



Inlet, N. of NW. Fame Island, 23—25 m, hard clay (' s 1899) 1 sp., d. l.v; D:o, 

 Cape Steward, 1 km off the coast, 70° 27' N., 22°35' W., 13—18 fms, clay, stones, algse 

 ('77 1 899), 4 sps, max. h. 2.ß (striata). 



Newfoundland: 46°56'N., 52°28'W., 81 fms, sand (Ing. & Glad. Exp. w 1871) 

 many sps. These agree with the Greenland forma grandis by having many unequal 

 spiral keels (9 on the last whorl). One sp. is similar to var. striata, but it has a 

 wider umbilicus, an angular and an umbilical keel and alternating ribs; measurements: 

 h. 19.2; ap. 9; d. 19; wh. 7. In comparing this sp. with var. striata from Skans 

 Bay there is but a slight difference in the higher shell and the angular and umbih- 

 cal keels of the present form. — 46° 5' N., 51°44'W., 56 fms, sand, shells (Ing. & 

 Glad. Exp. ^7« 1871) 1 sh., h. 11.8; ap. 5.7; d. 12; wh. 67* (spiral cords 10, of which 

 2 primary; base convex, coarsely ribbed; no angular keel; a rather strong umbilical 

 keel; type with characters of var. striata. — 45°59'N., 51°49'W., 56 fms, sand (Ing. 

 & Glad. Exp. 1871) 1 sh., h. 21; ap. 8.5; d. 18.4; wh. 7 V2 (spiral keels 10 of 

 unequal strength ; base convex, striated ; no angular keel ; a rather strong umbilical 

 keel). 



Limits of formal variation: 



Norway ; 



h. 



4—5 



6—7 



9—10 



13—14 



max. 13.2 (Ulfsfjord) 







40 sps 



ap. 



2—2.7 



2.5—3.6 



4—4.9 



6.1 



6.1 









rnensiired 



d. 



4.1—6 



6-7.5 



8.5—9.9 



12.3 



12.3 











wh. 



41/2—5 



5 



5V2— 6 



7 



7 











Spitzbergen ; 



h. 



4-5 



6—7 



9—10 



13—14 



18-19 



21—22 



max. 21.4 (Tre 



urenburg Bay) 



75 sps 



ap 



2.5—3 



3.2—4.5 



4.2—6 



5.8—8.1 



8.2—10.4 



10.5 



10.5 





measured 



d. 



4 9—6 



6.6—8.3 



9—11.8 



12.5—15.9 



17.5—20.5 



21.4 



21 



.4 







wh. 





5 



5—6 



5V2-6'/2 



6V2 



7 



7 





North of Siberia 



h. 



4—5 



6—7 



9-10 



13—14 



18—19 



24—25 



max. 25 (Vega 



Exp.) 



and Behring Sea ; 



ap. 



2.3—3 



3.7—4,2 



5-5.7 



7.2—7.8 



9.4—10 



11.8—12.2 



12.2 





averages of 



d. 



4.9—6 



7—8.2 



10.2—11.5 



14.5— 15 6 



19—20 



26 



26 





variation 



wh. 



4'A 



47* 



5Vi 



6 



6V2 



7 



7 





Iceland; 



h. 



4—5 



6- 



-7 



9- 



10 



12- 



-13 



max.: 



type 12.8 (»Iceland») striata 20 (Berufjord) 







type 



type 



striata 



type 



striata 



type 



striata 







50 sps 



ap. 



2.1 -2.9 



3.1—3.9 



3.6—4.1 



4—5 



5.5—6 



5.2-6.2 



7—7.5 





6.2 10 



measured 



d. 



4.3—5.7 



6—7.3 



7—8 



8.5—10 



10.5—11.5 



10.8—12.2 



13.4—14.1 





11.6 21.8 • 





wh. 



41/2—5 



5— 5V2 



4 '/■-.— 5 



6— 6V2 





6V'4— 7 



5V4 





6V2 6V2 



West Greenland ; 



h. 



4—5 



6—7 



9—10 



13—14 



max. 14.2 (Kekertak) 







95 sps 



ap. 



2—3 



2.7 -4.1 



3.4-6 



5.5—7.8 



fi 











measured 



d. 



4.2— 5 8 



5.9-8 



8—11.3 



12—15.5 



10 











wh. 



4V--— 5 



5-572 



5V2— 6 



about 6^|^ 



6 









An examination of the sculpture shows that two extreme forms of this species 

 may be distinguished from one another, the typical M. cinerea of Couthouy and M. 

 striata of Broderip & Sowerby. The first is characterised by having from 4 to 6 

 prominent spiral ridges, alternating with smaller ones; only one prominent keel ap- 

 pears on the apical whorls; both an angular and an umbilical keel are generally pre- 

 sent; the base is flattened, smooth or finely striated. A form of a considerable height 



K. Sv. Vet, Akad. Hancl). Bd 48. N:o 1. 9 



