58 LAMELLIBRANCHIATA. 



Lastly, I may quote a remark by lap. Steenstrup •) with regard to Modiolaria faba: "Eben 

 dieselbe Eebensart (i.e. wie Mod. Icevigata, cf. p. 61) muss audi cine andere Muschel aus derselben 

 Abtheilung der Gattung Modiolus, namlich der Mytilus faba Fabr. fn. gronl., fiihren, denn Prof. 

 Steenstrup hatte mehrere in Spiritus aufbewahrte Exemplare aus Gronland in ahnlichen Byssus- 

 hiillen gesehen; die Hiillen waren durch aussere Faden theils an Sertularien- uud Corallinen-Zweige 

 geheftet uud ganz iuit denselben bedeckt, theils waren sie zwischen verschiedenen Ascidien eingewebt, 

 zum Theil selbst von den letztgenannten iiberwachsen". 



Crenella decussata Montagu. 



Mytilus decussatus Montagu, Test. Brit. Suppl., 1808, p. 69. — Crenella decussata Jeffreys, Brit. 



Conchol. II, 1863, p. 133, PI. 28, fig. 6; Sars, Moll. Reg. Arct. Norv., 1878, p. 31, PI. 3, fig. 4. 

 Modiola? cicercula Moller, Ind. Moll. Groenlandiae, 1842, p. 19. - Crenella decussata var. Morch, 



Rink's Gronland, 1857, p. 94; Arctic Manual, 1875, p. 133; Rink's Dan. Greenland, 1877, p. 442. 

 Crenella decussata Posselt, Medd. 0111 Gronland, XXIII, 1898, p. 19; Hagg, Ark. 



f. Zoologi, Bd. 2, Nr. 13, 1905, p. 113; Jensen, Medd. 0111 Gronland, XXIX, 1909, p. 329. 



The ''Ingolf" has taken this species at: 



.St. 129. N. W. of Iceland 117 fm. 6.5 C. 1 valve. 



86. W. of Iceland (Brede Bugt) . . . 76 - 4 spec. ec numerous valves. 



87. -- — ...no- 12 — ec numerous valves. 



The largest of these shells (St. 87) is 3.75 mm . 



West Greenland. 



Here C. decussata is common from the southernmost parts up to a least Upernivik (72°47' N. L,.). 

 It occurs on clay and sand and among fragments of shells, most frequently at 20— 50 fm. but also goes 

 higher up (10 fm.) as well as deeper down (200 fm.). The largest specimens measure 5.5 mm . — "It 

 spins, but the threads are so fine, that they can scarcely be seen with the naked eye and even under 

 the lens only in certain directions of the light" (H. P. C. Mol ler M.S.). 



East Greenland. 



A single specimen, 4.75 """. high, has been taken on the southern part of the coast at Ti- 

 ningnekelak (65 56' X. L.); according to Hagg (1. c.) a Swedish Expedition is said to have taken a very 

 small specimen in Franz Josephs Fjord, the outer part of Myskokse Fjord, at 116", fm. 



Iceland. 



When Morch wrote his review of the Mollusca of Iceland he did not himself know Crenella 

 decussata from the island, but was only able to report, that Jeffreys had seen a single specimen 



Extract in: Aiml. Bericht fiber die 24. Versamml. Deutscher Naturf. u. Aerzte in Kiel, 1S47, p. 222. 



