I s JAMKS A. GRIEG. [SEC. ARCT. EXP. FKAM 



both specimens with thick and thin valves may occur. Typical speci- 

 mens i if the form arctica have a length of 25 20 mm., and a height 

 ,.f 12.5 14 mm. Some specimens which may he referred to this form 

 have moreover a length of up to 3$ mm., and a height of 10.5 mm. 

 The form pltoladis s. rngosa has a length of 4047 mm., and a height 

 of 2i 25 mm. 



Lyonsia arenosa, MOLLER. 



Locality: 



July -1-t. I'.MHJ. Tlie winter harbour. Havnefjoril, ahont 20 in. Rocks and stones. 



July -C>. \Ve-l side of the entrance to Stordalen, Havnefjord, 16 20 m. ('.lay. 



>'-[)t. 19. <MV Forvisningsdalen, Gaasefjord, 4 40 in. Clay with small stones. 



>. |it. -JO. The head of the Gaasefjord. 6 40 in. Cluy with small stones. 



An-. I'.tiil. . ahout 40 in. 



Aug. 16. . ahout 14 in. 



In Havnefjord only a quite young specimen was ohtained 7.5 mm. 

 long. In Gaasefjord 10 specimens in all were collected, which were 

 15-20 mm. long. The height of their shells varied from 54",, to 

 04.25 " ,, of their length, while the breadth (thickness) varied between 

 .'57. 14" i, and 42 of their length. For purposes of comparison we 

 may state that JENSEN found in the case of some specimens from the 

 east coast of Greenland, that the height of the shell was 51.062.7% 

 of the length and the breadth 30.9 44.7 " o of the length. Some of 

 the specimens from Gaasefjord measure: 



Long. 20 mm. Lat. 16.7 mm. Grass. 10.5 mm. 

 26 ,, 15.5 10 



25 .. 15.5 .. 10.5 .. 



25 13.5 9.5 .. 



23.5 14,5 ., 9 , 



IS 10.5 .. 7.5 .. 



H.5 10 0.5 



15 .. '.1.5 .. 



The specimen- closely resemble the description and illustration which 



II \M < K gives of Ii/dHxid (jiltbosd {lf/un*t(i < i ri'i/oxit c<tr. xihirica LECIII ! 

 from I i;ivi- Strait. 



Thracia truncntn. TIHTON. 



I, o c a 1 i I y : 



July -''. IMC. I. The winlc-r harlmur. I lavneljnrd, I- in. A ^ninewhal del'nnned 

 -|H rim. -ii lljiiii;. l.s.fi nun.. I, at. I i .'> nun.. ( !ra^ '.I mm.). 



July -!'. I'.)MI. Tlie winter liarlidiir. I lavnefjnrd, ahonl id in. liork- ami 

 fine ~|ircimen ll.i.iii:. i:t mm., Lat. 10 mm., ( !ra 7 mm.) 

 \ the l\pical Inrm. the other on Ihe rontrary more 

 Ihe variely ilrn-.i-ii (',. O. SAI;-. 



