20 I.AMELUBRANXHIATA. 



e.g. 6, 8 (PL I, figs. 5a &b), 10 and 12. Sometimes the intermediate ribs are almost as well developed as 

 the primary, so that the difference is not appreciable, and the sculpture then assumes a certain res- 

 emblance to that in Pecten islandicus; it lacks however the characteristic intercostal, rasp-like structure 

 of the latter (PL I, figs. 5 c & di. Each primary rib again is composed of a varying number of small 

 ribs, which may be smooth but are usually rough (at least towards the periphery) from the presence 

 of small, erect scales (PL 1, fig. 5e). All the specimens to hand are grayish-yellow to straw- or orange- 

 vellow (elsewhere the colour is described as purple-red or rose-red). The largest specimens measured: 



Length Height Breadth 



8 - 

 7 - 

 7 - 



Distribution. Pecten aratus ranges from Morea through the Mediterranean to the Atlantic 

 off Soudan ("Talisman"), Pyreuean Peninsula, France and Ireland, as also north of .Shetland 1 ); further, 

 it occurs from Bohuslan along the coast of Norway to Lofoten 2 ). Lastly, the Danish investigations 

 have shown that it goes south of the Fseroes and south of Iceland and a good way up into the 

 Denmark Strait. Its vertical distribution is placed by Jeffreys at from 20 to 530 fm. ; the "Ingolf" 

 however has taken a living (though small) specimen at a depth of even 788 fm. (St. 10). 



Among the synonyms of this species Jeffreys gives Pecten bruei Payraudeau, but French 

 and Italian authors do not agree with him here. After examining a specimen of P. bruei (from 

 Corsica) sent to our Zoological Museum by Marchese di Monterosato, I consider there is no doubt, 

 that Jeffreys is right; this means at the same time that P.aratus is distributed in the Mediterranean. 



Pecten septemradiatus Miiller. 

 PL I, figs. 6a — c (var. sender). 



Ostr,<i septemradiata Miiller, Zool. Dan. Prodr., 1776, p. 248. — Pecten septemradiatus Jeffreys, Brit. 



Conchol. II, 1863, p. 62, PL 23, fig. 1. 



This species has been taken by the "Ingolf" at the following stations: 



St. 98. W. of Iceland 138 fm. 5.9/ C. Fragments of numerous valves. 



- 89. - - — 310 - 8.4" - 1 spec. 



9. SAY. - 295 - 5.8 - 1 spec, and 8 valves. 



136 - 6.0 - Fragments of 4 — 



- 85. - - 1 70 - — - 7 — 



■ 55- S. E. - 316 - 5.9 - 1 spec. 



6- - - 90 - 7.0 - 2 valves. 



1. N.W. of the Faeroes 132 - 7.2 - 7 spec. 



'I During my participation in the cruise of the "Michael Sars'' in 1902, I obtained a specimen at 6o°2i.5' N. L., 3 

 55'W.I,, [48 fm. 



Noman's record of its occurrence right up at 71 12' 30" N.L., 20° 30' 30" E.L., 135 fm. seems hardly credible and 

 11 probability on an erroneous determination (Niederland. Arch. f. Zoologie, Suppl. Bd. 1, 1SS1 — 83, No. 10 p. 3). 



