LAMELLIBRANCHIATA. I 15 



74°35' N. L., i8°i5' W. L 79 fm., mud and stones. 2 spec. 



Off Mackenzie Bay 58 - , mud. 10 



and the Belgica Expedition at the following places 1 ): 



75°5&5' N. L., i4°o8' W. L 15S fm., bottom-temp. 0.4" C. 1 spec. 



7735.5'- - i8°i2' - - 28-, -1-79- ,fl 



Thus, at East Greenland the typical A. crenata has been taken at 13 localities from / < 36' N. L. 

 — 77°35'.5 N. L., and at depths of 50— i6ofm. The largest specimens are 28" 



From West Greenland I have only seen it from the above-mentioned St. 29 of the "IngolF 

 and from Umanak, 250 fm., but I imagine that quite a number of the specimens, which Posselt records 

 in Consp. Faun. Groeul. simply as "Astarte crenatci\ belong to the typical form. The specimens to 

 hand from Umanak are remarkably short and on the whole much convex, as will be seen from the 



measurements below : 



Height Breadth 



Length Height ' ; Breadth 



fc Length Length 



21.5'"'". 16.3""". 75-8% u.6""». 54 



18.75 - T 5-5 - 82 -7 " IO - 2 " 544 



18 - 14.2 - 78.9 - 10.2 - 56.9 ■ 



17.5 - 14 - 80 - 9 - 5,1-4 - 



17 14 - 82.4 - 10.2 - 60 



Var. subaquilatera .Sower by. 

 PL IV, figs. 5 d and e. 

 Astarte submquilatera Sowerby, Thes. Conchyl. II, 1855, p. 780, PI. 167, fig. 13; Reeve, Couchol. I 

 XIX, 1S74, sp. 5, PL I, fig. 5. 



This resembles the typical crenata in the oval form of the shell, but the concentric ribs are 

 fewer in number and coarser; the periostracum on the whole darker, yellowish-brown, olive-coloured 



or brown. 



The form is besides subject to great variation, as will appear clearly from the measurements 

 below; it varies from the elongated-oval or elliptical to the orbicular, somewhat triangular: 



Locality Length Height 



Ingolf vSt. 27 27 """. 21.5 ""». 



- - 26.5 - 195 - 



- 32 24.5 - 18.25 " 



Julianehaab 24.5 - 2r-5 - 



Jan Maxell 30 - 22 



— 27.75 - 21.75- 



M Grieg, in Due d'Orleaus Croisiere oceanographique, [909, p ,1 



i,V 



