lOO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



ISOTELOIDES ? sp. undt. 



Plate 24, fig. 24 



This small fragmentary cranidium is presented here in order 

 to illustrate a group of trilobites that occurs occasionally, but of 

 which the material thus far is so poor that the characters cannot yet 

 be determined. The fragment bears a superficial resemblance to this 

 genus and on that account may be tentatively referred to it. 



Formation and locality.- — Ozarkian: (6711) Mons formation. Head 

 north fork Saskatchewan River, three miles (4.8 km.) south of 

 Wilcox Pass, Alberta, Canada. 



KAINELLA, new genus 



Hnngaia Walcott, 1913, Smithsonian Misc. Coll., Vol. 57, No. 12, p. 33t) 



(listed) ; idem, 1924, Vol. 75, No. i, p. 37. 

 Kainella Walcott, 1925, Smithsonian Misc. Coll., Vol. yj, No. 2, p. 14. (New 



name proposed.) 



This genus is clearly defined by the unusual direction of the facial 

 suture, together with the peculiarities of the associated pygidium. 

 No entire specimens have yet been found of any species belonging 

 to it. 



Glabella rectangular in outline, slightly rounded in front, relatively 

 flat in cross-section. Two sets of glabellar furrows are present in 

 front of the occipital furrow. The anterior set consists of two 

 oblique depressions, while the posterior ones are similar, though 

 longer, and are connected across the glabella by a very shallow 

 furrow. 



Eyes large and situated about the midlength of the glabella. 



Fixed cheeks very narrow. 



Facial suture outlining long narrow postero-lateral limbs, passes 

 aroimd the eyes and a short distance beyond, turns outward almost 

 at right angles to the glabella. The distance from this angle to the 

 frontal rim equals two-thirds or more of the length of the glabella. 

 The suture is intramarginal to the center. 



Frontal rim and border wide. Border between the glabella and 

 rim marked by rather pronounced, peculiar ridges, sHghtly irregular 

 in course and size. In the different species, these radiate from the 

 front of the glabella in groups of varying numbers. The stronger 

 ones usually start from two points of origin near the front inner 

 corners of the glabella and extend to and merge into the rim. The 

 weaker ones, originating in front and back and along the sides of 

 the glabella almost to the eyes, for the most part fail to reach the 



