53 I,AMELLIBRANCHIATA. 



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

 dieselbe Lebensart (i.e. wie Mod. Ucvigata, cf. p. 6i) muss audi eiiie andere Muscliel aus derselbeu 

 Abtheihuig der Gattung Modiolus, namlich der Alytilus faha Fabr. fn. gronl., fiiliren, deiin Prof. 

 Steenstrup hatte mehrere in Spiritus aufbewalirte Kxemplare aus Gronland in ahnlichen Byssus- 

 liiillen gesehen; die Hiillen waren durch aussere Faden theils an vSertnlarien- nnd Corallinen-Zweige 

 gelieftet und ganz mit denselben bedeckt, theils waren sie zwischen verschiedenen Ascidien eingewebt, 

 zum Theil selbst von den letztgenannten iiberwachsen". 



Crenella decussata Montagu. 



Mytilus dcciissatus Montagu, Test. Brit. Suppl., 1808, p. 69. — CrciicUa decussata Jeffreys, Brit. 



Conchol. II, 1S63, p. 133, PI. 28, fig. 6; Sars, Moll. Reg. Arct. Norv., 1878, p. 31, PI. 3, fig. 4. 

 Modiola? ciccrcula Moller, Ind. Moll. Groenlandise, 1842, p. 19- — Crciiclla 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. om Gronland, XXIII, i8g8, p. 19; Hagg, Ark. 



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



The "'Ingolf has taken this species at: 



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



86. W. of Iceland (Brede Bugt). . . 76 - 4 spec. &: numerous valve.s. 



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



The largest of these shells (St. 87) is 3.75 '""■. 



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 """. — "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. Moller M.S.). 



East Greenland. 



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

 ningnekelak (65^56' N.L,.); according to Hagg (I.e.) a Swedish Expedition is .said to have taken a very 

 small .specimen in Franz Josephs Fjord, the outer part of Myskokse Fjord, at iiG'/zfin- 



Iceland. 



When Morch wrote his review of the MoUnsca 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: Amtl, Bcricht iibcr die 24. Versaimnl. Deutsclicr Naturf. u. Aerzte in Kiel, 1847, p. 222. 



