266 The Ohio Journal of Science [Vol. XVII, No. 7 



Plate XII. 



Fig. 1. Trocliurus phlyctainodes, Green. Cast of type prepared by Green and 

 numbered 54 in his series of casts of Trilobites. Original found in the 

 Cedarville limestone at Springfield, Ohio. In this, and in the following 

 series of figures of species of Trochurus A represents the dorsal view of 

 the cephalon; B, anterior view of the dorsal part, secured by tilting the 

 cephalon until the anterior border is horizontal; C, anterior view of 

 cephalon, with the anterior border transverse to last position; D, 

 lateral view, with dorsal side on left in figures 1, 3 and 4, but forming 

 upper outline in figure 2. 



Fig. 2. Trochurus hanoverensis. Miller and Gurley. Type, numbered 6141 and 

 preserved in the Walker Museum of Chicago University. From the 

 Laurel limestone at Madison, Indiana. 



Fig. 3. Trochurus bymesanus, Miller and Gurley. Type, numbered 6839 and 

 preserved in the Walker Museum at Chicago University. From the 

 Laurel limestone at Madison, Indiana. A, E, enlarged two diameters. 

 In E, the cephalon is tilted toward the front so as to show the upper 

 outline of the third lateral lobes, a direct view of the occipital lobes, and 

 the posterior part of the fixed cheeks, their raised granulated pos- 

 terior border, however, being absent. 



Fig. 4. Trochurus halli. Original of figures 2 a, b, c, on plate 70 of volume 2 of 

 the Paleontology of New York, numbered 1826 in the American Museum 

 of Natural History in New York City. A, enlarged two diameters. 

 From the Rochester shale, near Albion, New York. 



Fig. 5. Callocystites sphaeroidalis. From an impression of a cast of the exterior, 

 crossed by a crack as described in the text; p, location of the discrete 

 half of the pectinirhomb on plate 15. From the Cedarville dolomite at 

 Springfield, Ohio. 



Fig. 6. Camarotoechia roadsi. A, brachial valve; B, pedicel valve; C, lateral 

 view; D, anterior view showing depth of sinus; E, cast of interior of 

 brachial valve of a second specimen, showing muscular area and median 

 septum. From the lower part of the West Union formation on the 

 southeastern margin of Hillsboro, Ohio. 



Fig. 7. Prosserella (?) sp. Two casts of the interiors of pedicel valves, showing 

 vertical lamella supporting the teeth, and also a median septal ridge. 

 From the Cedarville dolomite at Cedarville, Ohio. 



