NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 45 



not preserved. Test with shallow puncta, close together so that the 

 ornamentation, which is not very conspicuous, might be described 

 as intermediate between punctate and granulate; anterior border 

 with irregular raised lines. Length of cranidium 5.5 mm. 



Occurrence. — Collection cs-4, North Chatham. 



Discussion. — This form might be compared with Bonnia busa 

 (Walcott) which, however, has visible glabellar furrows and stronger 

 ornamentation. 



Disposition of material. — Figured specimen: U.S.N.M. 146042. 



BONNIA, species undetennined No. 4 

 Plate 12, figure 18 



Represented by a single, incomplete, somewhat deformed example. 

 Glabella seemingly more convex both transversely and longitudinally 

 than in the preceding form, although this feature may have been 

 accentuated by slight lateral compression. Glabella on the average 

 parallel-sided, with exceedingly shallow lateral furrows. Occipital 

 furrow deep and broad; occipital ring incomplete, seemingly 

 triangular and presumably spinose. Fixigenae incompletely pre- 

 served ; anterior border of average width, strongly slanted backward 

 laterally. Surface of test finely granulate, the granules on the pos- 

 terior part of the glabella showing a tendency to become arranged 

 in irregular, transverse ridges. Length of cranidium 7.5 mm. 



Occurrence. — Collection cs-4, North Chatham. 



Discussion. — The proportionately short and wide, strongly con- 

 vex, nonexpanding glabella seem to distinguish this form from de- 

 scribed species. It is quite possible that, were the pygidium known, this 

 form should be referred to Kootenia. The cranidium does not greatly 

 differ from Kootenia troyensis Resser, as redescribed and figured by 

 Lochman (1956), but no pygidia resembling that species were found 

 in the collection. 



Disposition of material. — Figured specimen: U.S.N.M. 146043. 



BONNIA, undetennined pygidium 



Plate 12, figure 17 



Represented by a few examples, the only complete specimen being 

 the one illustrated. Pygidium with relatively narrow, somewhat ta- 

 pered axis showing three rings plus a terminal unsegmented section, 

 reaching the border furrow. Pleural regions with four pairs of pleural 

 furrows, counting the anterior border furrow, and but traces of one 

 pair of interpleural furrows. Border furrow shallow, border flat. 



