22 LAMELLIBRAXCHIATA. 



and in the eastern Kattegat (its southern boundary lies in the Sound at Hveen Island). Further it is 

 very common along the Norwegian coast, right up to Varanger Fjord (7o°N.L.) and, as shown above, 

 our knowledge of its distribution has been extended to embrace also the Atlantic at the Faeroes and 

 at south and south-west Iceland. - The bathymetric distribution extends from 15 to over 300 fm. 



M. Sars considered P. septemradiatus (P. danicus Chemn.) as an arctic species 1 ), and G. O. Sars 

 inclines to the same view, as his father has found the same species very common in the fossil con- 

 dition in the older glacial marl. As will have been seen from the above list, the "Ingolf" has only 

 taken this bivalve at localities with fairly high temperature; nor has the species been found elsewhere, 

 where the conditions are "arctic" in the hydrographical sense of the word. As it is inconceivable, 

 that the above authors could have made an erroneous determination of this easily recognized species, 

 I venture to conclude that P. septemradiatus belongs to a layer, which has been deposited under 

 milder climatic conditions. I notice also, that W. C. Brogger has put forward quite the same view. 

 He writes namely 2 ): "When we see, what a considerable size this species attains to in the Isocardia- 

 clay (up to more than 62 n,ra ), there is no reason for believing it to be originally an arctic species, the 

 less so, as it does not occur at all in the living or fossil, high arctic fauna. It is therefore undoubt- 

 edly a typically boreal species". 



Pecten tigrinus Miiller. 



Pecten Hg(e)rinus Miiller, Zool.Dan. II, 1788, p. 26, Tab.6o, figs.6— 8; Jeffreys, Brit ConchoL II, 1863, 



p. 65, PL 23, fig. 2. 

 Pecten tiger in us Morch, Vidensk. Meddel. Naturh. Foreu. 1868, p. 226 and p. 229. 

 The "Ingolf has taken this species at: 



St. 86. W. of Iceland (Brede Bugt) 76 fm. 9 valves (fragments). 



Iceland. 



Jeffreys gives "Iceland" as the home of this pretty species, as also Morch, who mentions 

 Torell as his authority. In addition to the above locality from the "Ingolf, P. tigrinus has been 

 taken in recent years at the following places at South Iceland: 



63°i5'N.L,., 22°23'W.L 170— 1141'm. 1 valve. 



6 3°3°' — , 20 14' — 42 - 1 — 



Vestmannaeyjar 30 - , gravel with shells. 3 — 



49 - , clay with a little mud. 5 — 



63°2i'NX., i7 : 3i'W.L 69 - , black sand. 2 — 



3° 21 ' — . !/ x 5' 58 - , sand, stones, shell-gravel. 15 — 



°3°24' - - ) *7 5' — 7° - 1 black sand w. stones and shells. 1 spec, and 9 valves. 



The largest of these shells measures: length 21.5 mm , height 22 mm . 



M. Sars: Fossile Dyrelevninger fra QuartEerperioden, 1S65, p. 127. 

 I \V. C. Brogger: Om de senglaciale og postglaciale nivaforandriuger i Kristianiafeltet, 1900- 1901, p. 469. 



