LAMELLIBRANCHIATA. 



[I 7 



V a r. inflata II ag g. 

 PL IV, figs. 5h and i. 

 Asiatic crenata Gray var. inflata Hagg, Arkiv for Zoologi, I'd. 2, Nr. 2, 1904, p. 37, PL I, figs. | 

 Jensen, Medd. om Gronland, XXIX, 1909, p. 338. 



The shell is ventricose, approximating to the obliquely square, with the upper and lower 

 margins almost parallel, the anterior end short, rounded, the posterior end truncate; the concentric ribs 

 in general rather numerous and strong, sometimes however less prominent or even vanishing on a 

 larger or smaller part of the shell (very rarely even quite wanting, so that the shell only shows a 

 fine striation). Periostracum yellow or brownish-yellow. 



It is a small form; I have not seen any specimen larger than 19 """. 



Some measurements will show its limits of variation, from the oblong-trapeziform to almost 



quadratic, as also the more or less ventricose. 



Height Breadth 



Length Height Breadth 



Length Length 



19 """. 14.5 ,lini . 76-3% IO """• 5 2 -'* 



16.5 - 11.75 - 71.2 - 9.2 - 55.8 - 



I5-25- 12 78.7 - 8.5 - 55.7 - 



15 - " ll-l - 7-3 - A s -7 - 



The number of ribs may rise to ca. 40 and fall to ca. 24 or even fewer, as the umbonal region 

 is frequently without folds; quite smooth specimens, as mentioned, may also occur. In small speci- 

 mens the ribs are frequently sharp, almost as in the following variety. 



This variety has been taken at the following places at East Greenland by Danish Expeditions: 



Forsblads Fjord ca. 50 fm., clay with stones. 5 spec. 



— 90 — 50 - , clay with stones. Numerous spec. 



74 17' N. L., 15 20' W. L 127 - , clay with stones. 2 spec. 



and by the Swedish Expedition of 1900 at: 



72°25' N. L,., I7°56 W. h ea. 160 fm., stones and sand. 7 spec. 



Mouth of Franz Josefs Fjord io6--i58'_, - , mud. 1 



and S. of Jan May en by the Danish Expedition of 1S91 at: 



7o°2i N. L,., 8°25' W. L 160 fm., clay- - spec, (empr.5 1. 



I presume that it was this variety, of which the Austrian .Station took 3 specimens on the 

 north side of Jan Mayen, at a depth of 75— 95 fm.; E. I'.echer determined them as Astarte sulcata 

 d. C. (Osterr. Polarst. Jan Mayen, III, 1886, p. 71), but the latter is a warm-water form and the present 

 variety has some resemblance to it. 



V a r. acuticostata Jeffreys. 



PL IV, figs. 5 k, 1 and 111. 

 Astarte acuticostata Jeffreys M.S., Friele, Nyt Mag. I. Naturvidensk. 23 Bd., 1S77, 3 Hft, p. 1; ibid. 

 24 Bd., 1879, ]>. 22t,\ Jalirl). Deutsch. Malacozool. Gesellsch. 6 Bd., 1879, p. 2(17, PL 4, fig. 8; 



