H4 



LAMELWBRANCHIATA 



Astarte crenata is an extremely variable species and lias given rise to not a few "species"; 

 these I can only recognize as nominal, as my material contains transitions between them. The 

 specimens living in the waters of Iceland, Jan Mayen and Greenland must, therefore, in my opinion, 

 be arranged under the following varieties: forma typica, var. subcequilatera Sowb., var. crebricostata 

 Me. Amlv. & Forb., var. inflata Hagg and var. acuticostata Jeffr. 



Forma typica. 

 PI. IV, figs. 5 a, b and c. 

 Astarte crenata Reeve, Conchol. Icon. XIX, 1874, Astarte, sp. 9, PI. 2, fig. 9. - Astarte oblonga 

 Sower by, Thes. Conchyl. II, 1855, p. 781, PI. 167, fig. 19. -- Astarte crenata Gray f. typica 

 Jensen. Medd. 0111 Gronlaud, XXIX, 1909, p. 337. 



The shell oval, more or less convex, with numerous (ca. 50), relatively low, concentric ribs, 

 which disappear on the posterior part of the shell; periostracum light-coioured, yellowish. 



In its typical shape (PL IV, figs. 5 a and b) it is quite characteristic, but this again is subject 

 to great changes 'i- The ribs may be fewer and more prominent (PI. IV, fig. 5 c), so that the boundary 

 towards var. subcequilatera vanishes. All three dimensions are subject to considerable variations, as 

 will be seen from the accompanying measurements: 



Height Breadth 



Locality Length Height Breadth 



Length Length 



Hurry Inlet 23 mm . 17.5 mm . 76.1 °/ 10.5 mm . 45.7 °/ o 



Cape Hope.. 23.5 - 17.5 - 74.5 - 11.25- 47-9 - 



S. ]•'.. of Sabine Island 23.5 - 18.2 - 77.4 - 12.5 - 53.2 - 



26.5 - 21.5 - 81. 1 - 12 - 45.3 - 



This form occurs at East Greenland, where the Danish Expeditions 2 ) have taken it at the 

 following places: 



Hurry Inlet 50 fm., clay with stones. Numerous spec. 



Cape Hope 121 - 3 spec. 



Cape Tobin 120 - 1 spec. 



72°24' X. L., 19=42' \V. L 130 - 1 living & 2 empty spec. 



72°5i' - 20°23' .' W. L 124 - , clay. 1 spec, (empty). 



72° 53 ' - 20 C 3 6'W.L 96 - 6 - 



73°24' - - 20 - 106 - 2 — 



S. E. of Sabine Island no - , fine clay with stones and 



gravel. 10 spec. & some valves. 



and the Swedish Expedition of 1900 at the following places: 



25 N. L., 17 56' W. I,. ca. 160 fm., stones and sand. 5 spec. 



For some very short and convex specimens Hagg has set up the variety incostata (Ark. f. Zoologi, Bd. 2, Nr. 2, 

 ; "' pl - r i 1; -K a similar form, likewise with weakly developed and very densely placed ribs, is in our Museum 



from rmanak in West Greenland if. the following). 



crenata has for the rest been taken at East Greenland (Shannon 1st, 30 fm.) already in 1869—70 by "Die zweite 

 Nordpolarfahrt" cf. Wissenschaftl. Ergebnisse. II, 1874, p. 252 under the name of Astarte crebricostata). 



