276 bulletin: museum of comparative zoology. 



DiONIDE CONTRITA, Sp. nOV. 



This species is represented by only a single specimen, a rather poor 

 pygidium to which are attached parts of two segments of the thorax. 

 It would not be worthy of description were it not for the fact that 

 it belongs to the group with large pygidia. 



Cephalon not yet known. 



Thorax with narrow axial lobe and short segments, the outer ends of which 

 turn backward. 



Pygidium large, nearly semicircular but not quite twice as wide as long. 

 Axial lobe narrow, tapering gradually and regularly. The last four milli- 

 meters of the axis are broken off, but the anterior part shows eighteen rings, 

 and there were apparently about twenty-four pairs of ribs on the pleural 

 lobes, these being especially crowded at the posterior end. 



Me.vsurements: — Length of pygidium, 14.5 mm., Ai-idth about 24 mm. 

 The axial lobe is 5 mm. wide at the front. 



Horizon and Locality:— The only known specimen was collected 

 by the writer about 100 feet above the bottom of the Athens shale near 

 the Thomas farm three miles northeast of Blacksburg, Va. Holo- 

 type M. C. Z. 1,591. 



Raphiophoridae Angelin. 

 Raphiophorus powelli, sp. nov. 



Entire test broadly oval, nearly as wide as long. Cranidium approximately 

 semicircular in outline, the glabella projecting slightly in front of the cheeks. 

 Glabella obovate, prominently convex, with a small spine directed forward 

 and upward. At the base of the glabella there are two small narrow lobes, 

 cut off by the posterior glabellar furrows. Fixed cheeks depressed convex. 

 Free cheeks missing, but evidently narrow. Thorax with five segments, each 

 pleuron bearing a deep linear, straight, median groove. Pygidium short and 

 wide, with abruptly deflected posterior border. The pleural lobes bear two 

 pairs of faintly defined ribs which curve backward to the margin. 



Measurements: — Length, 10.5 mm., width 9 mm. Length cephalon 

 5 mm., width 9 mm. Width glabella at front, 3 mm., at back 2 mm. Length 

 thorax 2.5 mm., width axial lobe 2 mm. Length pygidium, 2.5 mm. {circa), 

 width 8 mm. 



This species most nearly resembles R. semicostatu^, differing only in 

 having a less rapidly expanding glabella, in the presence of glabellar 



