54 



LAMELLIBRANCHIATA. 



Modiolaria vitrca Morcli, Tiling til Rink's Gronland, 1857, p. 94; Arctic Manual, 1875, p. 133; Rink's 

 Dan. Greenland, 1877, p. 442. — Dacrydiuiii vifrcicm Friele, N>t. Mag. Naturvidensk., 1879, 

 p. 22; Posselt, Medd. om Gronland, XIX, 1895, p. 66; idem, ibid. XXIII, 1898, p. 21; Jensen, 

 Medd. om Gronland, XXIX, 1909, p. 325. 



The "Ingolf has taken this species at: 



St. 32. Davis Strait 318 fm. 3.9° C. 33 spec. 



- 28. - 420 - 3.5° - 30 — 



- 35- — 362 - 3-6° - 3 - 



- 24. — 1199 - 2.4° - 5 - 



- 115. S. of Jan Mayen 86 - 0.1° - 18 — and 25 valves. 



- 116. — 371 - — 0.4° - 2 valves (corresponding). 



- 117. — 1003 - — 1.0° - I spec. 



- loi. N. E. of Iceland 537 - --0.7° - i — 



- 124. N. of Iceland 495 - —0.6° - i — 



- 126. — 293 - — 0.5° - 12 — and 12 valves. 



- 128. — 194 - 0.6° - 27 - - 9 — 



- 87. W. of Iceland (Brede Bngt) no- 4 _ . 50 — | Quite small, 



I maximum 



- 86. — — 76 - I valve. gj^e i "'"' 



- 98. W. of Iceland 138 - 5.9° - 8 spec, and 25 valves. 



- 97- - - — 450 - 5-5° - I — 



- 90- - - - 568 - 4-4° - 2 - - 7 - 



- 85. S.W. of - 170 - 5 - 



- 80. — - — 935 - 4.0° - I — - I valve. 



- 78- — - - 799- 4-5°- 35 - -ca. 50 valves. 



- 58. E. - — 211- 0.8°- I valve. 



- 138. N. of the Faeroes 471 - —0.6° - 10 spec. 



The largest shell, namely of 7 """., is one from St. 58, E. of Iceland ; in the Davis Strait a size 

 of 5 """. is attained (St. 28) and S. of Jan Mayen a size of 5""". (vSt. 115 and 116). From the stations 

 west and south-west of Iceland the maximum size is 4 """. F~rom the two very deep stations, 24 and 

 117, the size is respectively only 3""". and 2.5""". 



There is considerable variation in regard to the form and thickness of the shell'). The spec- 

 imens from west and south-west of Iceland (St. 87, 86, 98, 97, 90, 85, 80 and 78) differ especially from the 

 typical D.vitrciuii in having a relatively elongated form and a less convex dorsal line; they greatly 

 resemble the Dacrydium occidcntalc of E. A. Smith ^) (West Indies, 390 fm.), but I have not thought 

 it right to separate these specimens as an independent species. 



1) Cf. also A. Locard, who distinguishes between tlie following varieties: minor, clongata, curta, incmvata, Tcntricosa 

 and albida; Kxped. scient. Travailleur-Talisman, Moll. Test., 11, 189S, p. 364. 



2) Zool. Chall. Exp., Part XXXV, 1885, p. 282, PI. 17, fig. i. 



