NO. 1985. NEW SPECIES OF SILURIAN FOSSILS— WILLIAMS. 325 



frequently than in the lot just described. The hinge area is covered 

 so that the spines are not in evidence. 



Specimen No. M1556.2 is an external cast of the exterior of a 

 pedicle valve 9 by 5^ mm., showing 4 spines on each side. The beak 

 is inconspicuous, but the body rises abruptly from the hinge margin, 

 forming a convex body with cardinal angles not much flattened, a 

 slight narrow depression along the middle. Radii are over 60 but 

 not 80. 



Specimen No. M1556.3 is the mold of exterior of a brachial (?) 

 valve, dimensions 12 by 6^, radii about 60, bifurcating frequently 

 and early, as do all the specimens from this locality. 



Specimen No. M1556.4 is a similar shell, but imperfect and a little 

 smaller, showing the same size and form as specimen from 5. 5 1.5 A 

 except in having a less flattened area at the cardinal angle, the rise 

 from the cardinal border is more rapid and the radii bifurcate more 

 frequently and earlier, increasing the number of radii at the margin. 



Specimens Nos. M1547.1-3 comprise another set from loc. No. 

 7.42.6A. M1547.1 is a somewhat distorted pedicle valve 11 by 6 mm. 

 The radii are not distinct over the whole surface, but will reach about 

 80 in number. No evidence of the spines can be seen ; the body rises 

 abruptly from hinge area and the cardinal angles are but slightly 

 flattened. 



Specimen No. M1547.2, dimensions about 10 by 7mm, somewhat 

 distorted convex and with distinct flattened area at cardinal angle, 

 body convex, about 65 radii. 



Specimen No. Ml 54 7. 3, a specimen of pedicle valve distorted 

 slightly and showing general characters of No. 1547.2. 



Specimen No. M1554 is an imperfect pedicle valve, dimension about 

 10 by 5 mm., radii about 60, one spine base evident; convex, broad 

 body with but slight flattening at ears. 



Specimen No. M1516, probably the interior of a brachial valve 

 slightly convex, regularly so in specimen, but as interpreted a concave 

 valve. Radii as near as can be estimated about 55, bifurcating 

 occasionally. 



Specimens Nos. M1555.1-5 are from loc. No. 5.33.8A; 1 and 2 are 

 quadrate low, convex forms which appear to be pedicle valves; 

 dimensions No. 1, 9 by 7 mm.; No. 2, 9^ by 6^ mm.; beaks low, 

 narrow, and rising gradually from hinge area, with broad flattened 

 area at angles, and the body only moderately convex; radii often 

 dichotomizing twice before reaching the front and resulting in a full 

 hundred at border, the lateral ones faint and finer than over body. 

 These come very close to Hall's Chonetes tenuistriata from the Arisaig. 

 The specimens Nos. 1 and 2 are a little longer proportionately than 

 Hall's figure; 3, another crushed specimen probably had near the 



