PLATK I.XII— CoutinuiMl 



Subgenus CAMAROPHORELLA, s.-gen. nov. 



Page 215. 

 Camakophorklla LKNTICULAKIS, While ;ill(l Wllilticlil. 



Fig. 46 All iiiteraal cast of the pedicle-valve ; showing' the cavity left by the spondylium an<l median sep- 

 tum. The external surface of the shell is smooth, the low. radiating- ridges shown in this figure 

 and in fig. 47, being imjiressions of internal sinuses, probably vascular in their natiu-e. X 2. 



Fig. 47. An internal cast of the Ijrachial valve ; showing the impressions of sjiondylium and median sep- 

 tum. In this valve the spondylium is flat and the sujiporting septum penetrates it, extending 

 for a short distance into the interior cavity of the shell. X 2. 



Fig. 48. A cardinal view of an internal cast of the pedicle-valve ; showing the tilling of the spondylium and 

 the cavities left by the median septum and the oblique dental plates. X 2. 

 Yellow sandstones of the Burlington gi'oiip. Burlington, Iowa. 



Genus LYCOPHORIA, Lahusen. 1885. 



Page 230. 



Lycophoria nucella, Daluuui. 



Figs. 49, 50. Dorsal and prc^tile views of a finely plicated, orbicular specimen. In tig. 4'J, the muscular area 



is faintly outlined through the substance of the brachial valve. 

 Pig. 51. The exterior of the brachial valve of a more STOngly plicated shell which has been somewliat worn 



in the nmbonal region, disclosing the outline of the elongate muscular area. 

 Fig. .52. A longitudinal median section of the two valves ; showing the thickening of the umlional region 



of the brachial valve and the projection of the cardinal process into the imibonal cavity of the 



pedicle-valve. 

 Fig. 53. Cardinal view of specimen transversely sectioned in the nmbonal region, the pedicle-valve being 



above j showing the dental plates and erect, bifurcate cardinal proce.'ss. X 2. 

 Lower Silurian. Near ISt. Petersburg, Mus^ia. 



