LAMELLIBRANCHIATA. 23 



Faeroes. 



In an appendix to "Fannnla Moll. Insnl. Fteroensinm" Morch (1. c.l lias added P. tigrinus to 

 the faiina of the islands, without however stating the locality. In recent years it has been taken at 

 many places round the islands at depths of 20 — 150 fni., as will appear from the following list: 



\'estmanhavn 10 — 30 fm. i valve. 



Nolso, deep hole at north end ca. 100 - i spec, and i valve. 



62°29'N.L., 7=37' W.L 60 - 2 valves. 



62"i6' — , 5^54' - 50- 60 - 5 - 



5 miles N.E. of east point of Myggenses . . 50 - 2 — 



7 — N.byE.- - - - — ca. 57 - i — 



13 — S. of Myggenassholm ca. 70 - 28 — 



6i''4o' N.L., 7^40' W.Iv 135 - 6 — 



6i°o6' - , 8'3o' — 61 - 2 — 



6o°55' - , 8°56' - 69 - I - 



5 miles S. S. E. of Bispen 50 - i — 



9 — E. S. E. - — ca. 70 - 22 — 



6 — N. byW. - Kalso 60 - 2 



1 1/2 — 2 miles off mouth of Bordovig. . . 20—30 - i spec. 



16 miles E.byS. of S. point of Nolso . . ca. 80 - 4 valves. 



Akralejte in N.57W. 12 miles ca. 150 - i spec, and 10 valves. 



13 miles \V. by S. of Munken ca. 150 - i — - 9° — 



The largest of these shells measures: length 32""., height 31.5""'. 



These shells from Iceland and the Faeroes vary greatly in regard to form, sculpture and colour. 

 Forbes and Hanley have given the following description which agrees well with our shells: "Some- 

 times the surface is otherwise smooth, sometimes there is a marginal belt of narrow and very closely 

 disposed depressed radiating costellse; occasionally these latter extend over the whole shell with or 

 without the presence of about five principal radiating ribs, which are rounded, generally broad, and 

 variable in amount of elevation (var. costata Jeffreys)".') In the last variety the margin of the shell 

 is sometimes inflexed. 



Distribution. P. tigrimis is distributed along the west coast of Europe from the north of 

 Spain to West Finmarken, also over the Faeroes to South and South-West Iceland; it goes further 

 into the Kattegat. The vertical distribution is given by Jeffreys as 5 — 180 fm. 



Remarks on P. tigrinus and P. stria tus. 



Pecten tigri7Uis and P. striates are as a rule most readily distinguished from one another by 

 the hindmost ears in the former being almost rudimentary, but well-developed in the latter; further, 

 the radiating ribs in P. striates are beset with short vaulted spines or prickles, whereas these are 

 lacking in P. tigrinus. Sometimes, however, it is not at all easy to separate them, as the posterior 



I) Forbes and Hanley: A history of British MoUusca, II, 1853, p. 286. 



