5« 



LAMELLIBRANCHIATA. 



var. substriata Gray. 

 PI. Ill, figs. 5a— b. 



Mytilus discors. arcticus Fabricius, K. D. Vidensk. Selsk. Skr. 1788, p. 453 (partim), figs. 2 & 3. 



Modiolaria Icevis Beck, in Gaimard, Voyage de la Recherche, PI. 17, figs. 3a— e. — Modiolaria 

 discors Morch, Vidensk. Medd. Naturh. Foren. 1868, p. 224. -- Modiolaria lavigata var. sub- 

 striata Posselt, Medd. om Gronland, XIX, 1895, p. 67; ibid. XXIII, 1898, p. 26; Jensen, 

 ibid. XXIX, 1909, p. 326. — Modiolaria substriata Hagg, Arch, for Zoologi, Bd. 2, No. 2, 1904, p. 25. 



The "Ingolf has taken this species at: 



St. 33. Davis Strait 35 fm. 0.8° C. 1 spec. ^ var. 



. 34. — 55 - l — very young J hvvigata. 



- 119. Norwegian Sea 1010 - 1 young (empty), vox. substriata. 



At West Greenland the species is very common from the southernmost part of the land as 

 far northwards as the investigations extend, namely to N. W. of Cape York; on the American side it 

 is still met with in Franklin Pierce-Bay at 79°25'N. L,. It prefers shallow water, 0—30 fin., but it is 

 said to live also in greater depths, down to 100 and 200 fm. The variety substriata is less common 

 than lavigata. The largest specimens at my disposal of var. lavigata measure 46 """., of var. substriata 

 30""".; O. Fabricius mentions specimens of up to 50™'". 



At East Greenland the species has been taken at many places, sometimes in large numbers, 

 from Angmagssalik as far north as collections have been made (Shannon Island at 75 — 75V2 N. L.). 

 The depths noted are 0—30 fm. The variety laevigata is also by far the most abundant here; the 

 largest specimen of this variety measures 36.5 mm ., of substriata 32 mm . 



Jan Mayen. The Austrian Expedition took 13 specimens up to 28 mm . long on the north side 

 of the island, at a depth of 8 — 13 fm. The Danish Exped. of 1900 took some smaller specimens at 

 15 and 50 — 60 fm. 



At Iceland the species is probably common all round the island, from lowest water 1 ) and (in 

 small specimens) out to 50 — 60 fm.; the localities mentioned below hardly give a correct picture of its 

 distribution, as only few dredgiugs were made in very shallow water, where the species mainly lives. 

 The variety lavigata, which is the most frequent, reaches a length of 48 mm ., and among the var. 

 substriata there is one of 52 """. 



East Iceland: 



Lonsvik 8 — 10 fm., fine black sand. 1 spec. 



Berufjordr, Djupivogr 3 - , on Laminaria rhizoids. 2 



6 - , mud with black sand. 1 — 



8- 2 — 



10 - 3 — 



Breiddalsvik 14 - 1 — 



') A. C. J oh an sen records Modiolaria lavigata among- the Molluscs which occurred in the greatest abundauce 2—3 

 meters below the high water mark at the coasts of Iceland. Vidensk. Medd. Naturh. Foren. 1902, p. 3S7. 



