Some Remarks on Phimidites Jamesi. 275 



"General form of plates triangular, with the apex a little inclined 

 to one side, the lateral margins gradually and rapidly diverging from 

 the initial point, one of them considerably longer than the other. 

 Basal margin sigmoidal, the convex portion situated next to the longest 

 lateral face, the concave portion to the shorter, and the shorter lateral 

 mai'gin deflected downwards in some cases (probably the marginal row 

 of plates)." 



" The surface of the plates is flattened or slightly convex on the 

 sides, and very faintly depressed along the middle, the whole marked 

 by rather closely arranged, annulating and scaliform transverse lines 

 parallel with the basal or sigmoidal margin, and marking stages of 

 growth. These transverse lines are usually faintest near the apex, and 

 gradually increase in width with the increased growth of the plate, but 

 in some cases they are quite irregular in their distances." 



"The length from the apex to the basal margin of the plate is 

 usually a little greater than the transverse diameter, and seldom exceeds 

 a sixteenth of an inch, the largest specimens seen not measuring a line 

 in their greatest diameter." 



Fig. 19. Plamiihlei ("> ) jnmen , magnified 2 diameters. 



It will be observed, that Hall and Whitfield were in possession only 

 of detached plates, which they determined to belong to the sub-class 

 Cirrlpedes, and referred to the genus PlumuUtes. Such detached plates 

 are common, and found at all elevations throughout the Cincinnati 

 Group. While the general form is triangular, they are more or less 

 inequilateral, and differ from each other very much in form and size. 

 And, I can scarcely think, that the transverse lines on the plates, 

 mark the stages of growth, as suggested by the foregoing description. 



J. Kelly O'Neall, of Lebanon, found a specimen, which he has 

 kindly furnished to me for illustration and des^cription as shown by 

 Fig. 19. It consists of two series of these plates, apparently connected 

 at one end by an overlapping plate, but, which, gradually separate 

 toward the other end. Each series is arranged in the form of a curve, 

 but, it is possible that the curve is the result of accident or pressure. 

 There are ten plates in each series, more than half of each of which 

 is covered by the overlapping plate, except the first plate in each 



