NO. 13 DIKELOCEPHALUS AND OTHER GENERA 379 



22 mm. in length. The frontal limb is proportionally longer than 

 that of either of the above species, and there is a peculiar flattening 

 of the frontal border in advance of the glabella with a narrow trans- 

 verse ridge outlining the broad, downward sloping frontal margin. 

 The glabella expands a little anteriorly. 



Surface of test apparently smooth. 



Formation and locality. — Upper Cambrian: (i2g: 50 feet above 

 I2J) Arbuckle limestone (lower part) ; Wichita jNIountains, south 

 side about 8 miles (12.8 km.) west of Fort Sill and in a small hill 

 2 miles (3.2 km.) southwest of Signal Mountain, Comanche County, 

 Oklahoma. Fossil horizon No. 3 of E. O. Ulrich, 100 feet (30.4 m.) 

 from base of hill. Collected October 9, 1901. 



SAUKIA ? ? LEPTJENARUM (Wiman) 



Dicellocephalus ? leptcenarum Wiman, 1907, Arkiv for Zoologi, Bd. 3, 

 No. 24, p. 5, pi. 2, figs. 1-3. (Described and illustrated as a new species.) 



This species is founded on a small pygidium that resembles the 

 pygidium of Saiikia leucosia (pi. 67, figs. 13, 13a). It is possible 

 but not probable that the pygidium belongs to a species of Sankia. 



Formation and locality. — Ordovician : Leptcciia limestone, west 

 Baltic region, Sweden. 



SAUKIA LEUCOSIA, new species 



Plate 67, figs. 14-170 



This fine species is represented by specimens of the cranidium, 

 free cheeks, and possibly the pygidium. It differs from the associated 

 Saukia pyrene (pi. 67, figs. 18-20) by having a broad, rounded 

 frontal limb, a character that serves also to distinguish it from S. 

 pepinensis (pi. 6y, figs. 1-5) and S. stosei (pi. 69, fig. 3). 



Formation and locality. — Upper Cambrian : St. Lawrence forma- 

 tion (78), quarry near St. Croix River, in suburbs of Osceola, Polk 

 County, Wisconsin (L. C. Wooster, 1883) . 



Franconia formation (99), Minneiska (Miniska), on Mississippi 

 River, near the line between Wabasha and Winona Counties, Minne- 

 sota (Cooper Curtice, 1884). 



SAUKIA LODENSIS (Whitfield) 



Plate 65, figs. 1-3 



Dikcllocephalus lodensis Whitfield, 1880, Ann. Rept. Wis. Geol. Survey for 



1879, p. 51. (Founds species on a free cheek.) 

 Dikellocephalus lodensis Whitfield, 1882, Geol. Wisconsin, Vol. 4, p. 188, 



pi. 10, fig. 14; p. 341; pi. 27, figs 12-13. (Reprints former description 



and illustrates free cheek, and on pi. 27, figs. 12 and 13, a nearly entire 



dorsal shield.) 



