REPORT OF THE DIRECTOR IQIQ lO/ 



■m. 



Fig. 60 Fig. 61 



Fig. 60 Tet ran o t a bid'orsata (Hall). Nat. size. Fig. 61 Ko keno - 

 spira rara nov. x2. 



The specimen exhibits the following characters : 



Description. Shell small, probably subglobular in form, 9 mm 

 wide and 7.5 mm long, in vertically compressed condition: height 

 not known ; volutions broad enlarging graduall}'- to the aperture ; 

 slit-band wide, smooth, slightly concave with filiform edges, the 

 sides evenly and strongly convex to the umbilicus, which is too much 

 compressed to show its nature. Aperture but slightly expanded 

 apparently with but a shallow central emargination of the dorsal 

 side. Surface on each side of slit-band with five (or more?) 

 sharply elevated, outwardly curving revolving lines which alternate 

 with finer ones that do not reach the aperture. Growth lines indis- 

 tinct, except some very coarse lines paralleling the frontal margin. 



From K . c o s t a 1 i s our species is at once distinguished by the 

 alternation of the revolving striae, and from K. esthona in the 

 lesser prominence of the slit-band. 



Schuchert states regarding the two Frobisher Bay specimens, 

 which he identified with K. costalis, that they agree with the 

 Minnesota form, of which there are two specimens in the National 

 Museum, excepting the number of revolving lines. " Of these there 

 are seven in the Minnesota specimens, while in the Arctic individuals 

 there are from eleven to twelve, of which the fourth, sixth and eighth 

 are the most prominent. The first, second, fourth, sixth and eighth 

 revolving lines are continuous into the aperture, the others being 

 interpolated on the last volution." This description leaves hardly 

 any doubt that the Frobisher form is identical with ours, and 

 further that the type thus marked by alternating striae should be 

 distinguished from the Minnesota form with uniform lines. 



Bibliography 

 Hall, James. Palaeontology o£ New York. v. i, 18A7 

 Winchell, N. H. & Schuchert, C. Geological and Natural History Survey 



of Minnesota, v. 3, pt i, Palaeontology. Brachiopoda. 1895 

 Ulrich, E. O. & Scofield, W. S. ibid. v. 3, pt 2 Gastropoda, 1897, p. 813. 



