150 Howard Fox — Devonian Rocks and Fossils 



as a rale the summit apertures are defective, but on the whole 

 these fossils are better preserved than other organic remains in the 

 same rock. 



The specimens are variously elongate, gradually tapering cones, 

 ranging from 30 mm. to 72 mm. in length and with a summit 

 breadth of 7-9 mm. The most complete example (PL VII, Fig. 1) 

 is a cone, 35 mm. in length, showing the outer surface of the test, 

 but the ornamentation is only distinguishable in its upper portion. 

 The upper margin, apparently perfect, has a gently convex outline, 

 and including the lateral processes is about 9 mm. in breadth. The 

 surface of the central cone exhibits delicate arched growth-lines 

 following the contour of the aperture, and at intervals of about 

 2*5 mm. it is crossed by stronger raised lines, which on either side 

 of the cone are prolonged downwards to form the anterior margins 

 of small flattened or slightly concave processes or flaps, which 

 extend obliquely for a distance of l'o-2 mm. from the cone. There 

 are in this specimen sixteen of the ear-shaped processes ; they are 

 disposed so that the posterior margin of each dips slightly under 

 the front edge of the one next below it in the series. The three or 

 four processes on either side of the lower part of the cone appear to 

 have coalesced together so as to form a narrow continuous plate^ 

 ■which extends round and slightly beyond the point of the cone. 

 In another specimen, 72 mm. in length, there are about thirty-four 

 pairs of processes, which are somewhat triangular in outline. 

 A transverse section of a specimen similar to Fig. 1 is distinctly 

 elliptical in outline. 



In the forni represented in PI. VII, Figs. 2 and 3, the cone has 

 been weathered so as to expose the interior longitudinal rod or 

 thickening of a portion of the interior of the test. The specimen 

 is imperfect, and a joint in the shale has divided it into two parts. 

 Above the fracture, the exterior of the test is shown crossed by striae 

 with a slightly concave curve, whilst below the line of fracture the 

 interior of the cone is laid bare by weathering, and a central 

 rod-like body, unequall3'^ thickened at intervals and bordered by 

 depressions on either side, projects slightly above the bordering 

 wall of the test (PI. VII, Fig. 3). The lateral flaps or processes 

 are very distinctly striated, and in contrast with those of the 

 specimen mentioned above (Fig. 1) the processes and the striae- 

 have a slightly upward direction. This difference may perhaps 

 be explained by supposing that the side of the shell exposed in this 

 examjDle is the reverse of that shown in Fig. 1. Owing to the fact 

 that only one side of a specimen can be examined, it is not 

 practicable to determine if the characters of the dorsal or ventral 

 side in this form are similar or not. 



Another aspect of the interior rod is seen in the middle half of 

 a specimen (PI. VII, Fig. 4) in which the striated shelly exterior 

 has been weathered away. It here appears as a stx-aight, slender, 

 nearly smooth, cylindrical rod, just wathin the wall of the cone. In 

 the short length of it exposed there is no connection with the latei'al 

 processes apparent. The nature and function of this interior rod 



