LAMELLIBRANCHIATA. 37 



If these suppositions prove to be well-fotiiuled, tlie s\ii()ii\iii\' of llic Atlantic form will then 

 be as follows: 



Pecten undatus Verrill 6c vSmith'i- 

 1S76. Picfcii fragilis Jeffreys, Ann. May. Nat. Mist. (4) XVIII, p. 424 (partini). - Northern Atlantic 



(between Ireland and Greenland), 1450 — 1785 fm. 

 1879. /-'.yw^'/V/.s Jeffreys, Proc. Zool. Soc. Lond. p. 561 (partini) (non PI. 45, fig. i). — W. of Ireland, 420 fni. 

 1885. P.uitdafiis Verrill &; Smith, Trans. Conn. Acad. VI, p. 444, PI. 44, fig. 21. — Off Virginia, 



1423 fm. 

 1885. P.pudicus E. A. vSmith, Chall. Rep., XIII, Laniellibranchiata, p. 302, PI. 21, fig. 8. — Southern 



Ocean E. of JMariou Island, 1375 fni. 

 1888. P. biscayritsis Locard, Contrib. a la faune malacologique fran9aise, XI Monogr. des esp. app. 



an Genre Pecten, p. 144. — Bay of Biscay, "zones profondes". 



1897. Clilamys (Psaidaviussiiun) pudica Dautzenberg & Fischer, Mem. Soc. Zool. de P'rance, 10, 



p. 191. — Azores, 1846 fm. 



1898. Pccfni Biscayoisis Locard, Plxped. scient. du Travailleur et du Talisman, Moll. Test. II, p. 400. 



— N. of Spain, 1353 m.; off Santander, i96oni. ; W. of Soudan, 2635 m. 



1898. Hyalopccfiii dilccfiis Verrill & Bush, Proc. Unit. Stat. Nat. Mn.s., 20, p. 836, PI. 97, fi.g. 9. — 



Off Marthas Vineyard, 1813 fm. 



1899. H.dilrctits Verrill & Bush, Trans. Conn. Acad., X, p. go. 

 1899. H. It II da fits Verrill & Bush, ibid., PI. 18, fig. 5. 



To this species I refer a fragment of a left valve, taken by the "Ingolf" at 

 vSt. 18. Entrance to the Denmark vStrait 1135 fm. 3.0° C. 



Pecten maxim us Linne. 

 Ostrca maxiiiia Linne, Sy.st. Nat. ed. 12, i, 2, 1767, p. 1144. — Pectcii ina.xiinus Jeffreys, Brit. Conchol. II, 

 1863, p. 73, PL 24. 



A fragment, ancient in appearance, of a large valve (the ventricose right valve) was obtained 

 by nie in the dredge on Faeroe Bank (6o°55' N. L., 8°56' W. L.) at a depth of 69 fm. 



Distribution. The Western Mediterranean 2) and along Europe from the Canary Isles and 

 Madeira to Scotland, Southern Norway, Skager Rak and Bohnslan. 



Amussium lucidum Jeffreys. 

 PI. II, figs. 3 a — c. 

 Plairoiiccfia htcida Jeffreys, in Wyville Thomson's Depths of the vSea, 1873, p. 464, fig. 78.') — 

 Amusshtm lucidum Jeffreys, Ann. Alag. Nat. Hist. (4) XVIII, 1876, p.425; Jeffreys, Proc. 



1) The name Pecten fragilis Jeffreys cannot be taken into consideration, as on the one hand, as shown, it embraces 

 heterogenous forms, on the other it has been used, as Locard has shown, both by Chemnitz and by Montagu for other 

 species. More doubtful is the question between the names undatus and pudicus, as they were brought into use in the same jear. 



2) Cf. Monterosato: Revision de quelques Pecten des mers d'Europe (Jouni. de Conchyliologie, 1899, Nr. 3, p. 4). 



3) Dall is of opinion, that only the figure to the left represents A. Ittctdum, whereas the figure to the right (b) is 

 of another species, namely A. Pourt alesianum ; Bull. Mus. Comp. Zool., vol. XII, No. 6, p. 211. 



