400 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



In addition to the above localities, pygidia have been tentatively 

 referred to B. mimula from two other localities : 



(n7b) Maryville limestone; Buckingham Ford road. 3.5 miles 

 (5.6 km.) southeast of Greeneville, Greene County, Tennessee; and 

 (i3ga) ConasaUga formation; bluish limestones in shales on road 

 near Wades Gap, near Chepultepec, Jefferson County, Alabama. 



MARYVILLIA, new genus 



The cranidium is not unlike that of Blountia except that the frontal 

 limb and border merge into each other w^ithout a very definite line of 

 demarcation betw^een them. The smooth glabella, medium width of 

 fixed cheeks and medium size palpebral lobes all are similar to the 

 same parts of Blountia, but at the same time there is a suppressing of 

 the relief of the glabella and fixed cheeks that gives a very distinctive 

 character to the cranidium. The pygidia associated with the cranidia 

 of both species, M. arion and M. ariston, are elongate with about 14 

 anchylosed segments as shown by the interior of the test of the axial 

 lobe (pi. 64, figs. 4a and 5a). This type of pygidium suggests transi- 

 tion from Blountia to Tsinania as represented by such species as 

 T. canens Walcott, T. ceres Walcott, T. dictys from the Upper Cam- 

 brian of eastern China.' 



Surface of exterior of test with shallow pits and on some specimens 

 it is apparently punctate. 



Genotype. — Mayyvillia arion Walcott. 



MARYVILLIA ARION, new species 



Plate 64, figs. 4, 4(/-i- 



This species is represented by numerous specimens of the crani- 

 dium and pygidium from localities where both were associated in the 

 same hand specimens of limestone. It is this association in different 

 localities that leads to the conclusion that the cranidium and pygidium 

 belong to one species. 



The characters of the cranidium are well indicated by figures 4, 

 4'. The very narrow occipital ring with the almost flat glabella and 

 the rapidly sloping, fixed cheeks are the most noticeable features. 



The pygidium is found only as the interior of the test and the 

 cast of it ; the test clings in the matrix owing to its roughened outer 

 surface which is more or less compactly covered by shallow pits or 



^Research in China, Vol. 3, The Cambrian Faunas of China, 1913. pl- ^3. figs. 

 ^b, y, Aa, 5a, 6. 



