374 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 5/ 



nected at the center ; third furrow usually faintly defined and repre- 

 sented by a short furrow on each side of the glabella that extends 

 directly inward instead of slightly backward as in the first and second 

 glabellar furrows. Free cheeks rather large and convex. 



Palpebral lobe prominent, about one-half the length of the glabella ; 

 marked by a strong intramarginal furrow ; anterior margin a little in 

 advance of the transverse center of the glabella. Eye lobe narrow. 



The facial sutures cut the posterior margin well out toward the 

 genal spine and curve quickly inward to the posterior margin of the 

 eye, outlining the narrow postero-lateral limbs of the cranidium ; 

 arching outward around the palpebral lobes they curve slightly out- 

 ward and then inward so as to cut the front margin on a longitudinal 

 line passing through the outer margin of the palpebral lobe. 



Thorax with 12 segments. Axial lobe convex with each segment 

 gently rounded and with a very faint longitudinal furrow on each 

 side that serves to define a slight swelling at the end of each segment. 

 Pleural lobes of nearly uniform width throughout and with each 

 segment terminating in a short falcate end ; pleural furrows narrow, 

 deep, and crossing the pleurae obliquely from the anterior inner end 

 to the posterior third of the falcate terminal section. 



Pygidium transversely and approximately semicircular with the 

 anterior margin arched forward ; strongly trilobed. Axial lobe con- 

 vex, with four to eight transverse segments. Pleural lobes with flat- 

 tened margin that is usually free from pleural and segmental fur- 

 rows ; surface marked by segmental lines and narrow pleural furrows 

 of the same general character as the pleural furrows of the thoracic 

 segments. 



Surface pustulose as in Saiikia lodensis (pi. 65, figs, i, 2) to 

 minutely granulose as in Saukia pepinensis (pi. 67). 



Dimensions. — The largest specimen of the typical species is illus- 

 trated by figure i, plate 65. None of the species referred to Saukia 

 approaches in size Dikelocephalus minncsotcnsis (pi. 60). 



Genotype. — Dikelocephahts lodensis Whitfield (pi. 65, fig. i). 



The genus Saukia ' is proposed for a group of trilobites that have 

 heretofore been referred to Dikelocephalus. It differs from the latter 

 in having a comparatively narrow frontal limb to the cephalon ; a pro- 

 portionately longer glabella that may be narrowed opposite the pal- 

 pebral lobes and slightly expanded anteriorly and that is more elon- 

 gate proportionally than in Dikelocephalus. As far as known the 



^ Indian name Sauk applied to Sauk County, Wisconsin, in which localities 

 specimens of Saukia lodensis occur. 



