l68 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



NoRWOODiD^, new family 



Proparia with 8 or 9 segments ; strongly developed spines at genal 

 angles ; eyes small, but well developed. 



This family combines primitive characters with those of a more 

 highly developed type. The cranidium with its Ptychoparia-like. 

 glabella and small eyes, and the broad pleural furrows, are primitive 

 (Calymenidae-like), while the few segments of the thorax (9) and 

 the relatively large pygidium suggest the subfamily Phacopinse. 



NORWOODIA, new genus 



General form a broad ellipse, moderately convex, with pleural 

 lobes more or less flattened. Cephalon semicircular with the genal 

 angles prolonged as strong spines ; cranidium elongate with narrow 

 fixed cheeks and medium-sized palpebral lobes ; glabella conical and 

 marked with three pairs of short lateral furrows ; frontal limb dis- 

 tinct or merging into the frontal border ; postero-lateral limbs large, 

 transverse, and carrying a strong spine at the genal angle; free 

 cheeks large, roughly subtriangular, and with the eye lobe at the 

 inner posterior angle. 



Thorax with eight or nine transverse segments ; axial lobe strong, 

 convex; pleural lobes with each segment having a broad, strong 

 median furrow that terminates just within the more or less bluntly 

 falcate pointed extremity. A sharp, slender median spine similar 

 to the occipital spine of the cephalon occurs on the third, fifth, and 

 seventh segments of the thorax of N. tenera, as shown by figure 2d, 

 plate 28, which has the spine of the seventh segment attached to the 

 axial lobe; the point of attachment is also shown on the axial lobe 

 of figure 2h ; similar thoracic spines occur on N. gracilis (fig. 2f, 

 pi. 27) and N. simplex (fig. 3&). 



Pygidium transverse; axial lobe strong and divided by narrow 

 transverse furrows into two or three rings and a terminal section ; 

 pleural lobes broad and marked by backward-curving narrow 

 furrows. 



Surface minutely granular with larger scattered granules on 

 Norwoodia tenera, which is the only species preserving the test in 

 good condition. 



Dimensions. — All the species of the genus are small. A dorsal 

 shield of Norivoodia gracilis has a length of 11 mm. One of A''. 

 saffordi, 8 mm., and the largest cranidium of A^ tenera has a length 

 of 3.5 mm. 



Genotype. — Norwoodia gracilis Walcott (pi. 27, figs. 2, 2a-b). 



