NO. 1985. NEW SPECIES OF SILURIAN FOSSILS— WILLIAMS. 327 



flattened; radii only occasionally bifurcated and that mostly near 

 edge, and total about 80. These aU retain the typical characters of 

 the species CJionetes edmundsi with certain fluctuations. 



Although this species is found associated with C. novascotica, it 

 difi'ers from the latter m the greater convexity of the pedicle valve, 

 deeper concavity of brachial valve, and the radiating hues on the 

 surface are much finer, rarely over 80 and often scarcely 60. The 

 species is of the type of C. striatella Dalman, but differs from that form 

 (as seen typically at Eastport in the fauna 5.33.8B) in its smaller and 

 shorter form and in its less lateral extension. The average size is 

 about 8 by 13 mm., whereas a small form of typical C. striatella is 

 9 by 15 (M1420.7), another (M1420.4) is 9^ by 18^. The rays are 

 about the same size as in C. striatella, as are also the cardinal spines, 

 and the species may be taken as representing the form represented by 

 Davidson's smaller figure 25a and by De Konnick's figures 5a, h, c, d, 

 of shorter form with proportions 14-22. The ordinary proportions 

 given by De Konnick are 100; 182; 27; 8 as compared with the 100; 

 157; 40; 9, the more swollen form. 



CHONETES COBSCOOKI, new species. 



Plate 29, fig. 5. 

 Cf. 1860. Chonetes novascotica Hall, Canadian Nat. Geol., vol. 5, p. 144, fig. 2. 



Shells are flattened with the front often a Httle arching, but the 

 umbonal portion is always low and but sHghtly rising above the 

 cardinal margin. The brachial valve is nearly flat, slightly concave. 

 The spines are 5 or 6 on each side and slender, curved inward, outer 

 ones longer than umer. The radii bifurcate frequently over the 

 whole surface and at two or three points in course of growth, resulting 

 in a nearly uniform fine size of radii which at the front reach a number 

 as great as 150 or 200. 



In the typical specimens of this locality the arching over at the 

 front is slight and the form is therefore flattened-convex. A central 

 radius is occasionally present with double the size of the ordinary 

 radii, running from the beak to the front without bifurcation. Speci- 

 mens are seen on the slabs as small as 11 mm. broad and 7 or 8 mm. 

 long, and one specimen is 17 broad by 9 long. The lateral growth 

 does not reach double the length, though the width is generally three- 

 quarters greater than the length. 



Formation and locality. — Edmunds formation, calcareous shales 

 south of Field Point, west shore Cobscook River, Edmunds Township 

 (loc. 8.21. lA). 



Holotype.— Cat. No. 58949, U.S.N.M. 



Comments. — ^The dimensions of Hall's flgures of the type of CJionetes 

 nova scoticus are, breadth 20^ at the hinge margin and 22 in middle of 

 shell and 15 mm. from beak to front. The form called CTionstes 



