THE NATURAL HISTORY SURVEY. 2T/ 



In 1873, Meek* identified as /. insignis a species from the 

 dolomitic Niagaran limestone at Springfield, Ohio. He pointed 

 put several characters, however, in which the Ohio specimens 

 failed to agree with Hall's original description an'd illustrations, 

 and suggested that if -they should prove to be distinct that the 

 species might be known as /. springfieldensis. The Ohio species 

 certainly is distinct from the 7. insignis and the name 7. spring- 

 fieldensis is used to designate it in the bibliographic list in this 

 Bulletin. The species does possess the elongate dorsal furrows 

 terminating in pits, and also the lip-like margin of the cephalon 

 of 7.' insignis, but the head is proportionally shorter and broader, 

 and the eyes are more protuberant, the species approaching in 

 these respects more closely to 7. harrisi described in this Bul- 

 letin. The pygidium of 7. springfieldensis is altogether different 

 from that of 7. insignis, as has been pointed out by Meek. 



In his Wisconsin report Whitfieldf has identified I. insignis, 

 but the cephalon he illustrates lacks the strong, elongate dorsal 

 'furrows terminating in pits so characteristic of 7. insignis, and 

 the pygidium, although possessing the correct outline and the 

 median ridge of 7. insignis, has a very different profile, the 

 greatest convexity being much more posterior in position than^ 

 in the Hawthorn specimens. In all probability Whi.tfield's 

 specimens represent an undestribed species of the genus. 



Foerste'sJ identification of the species from the Clinton 

 of Ohio is undoubtedly incorrect. His description is brief and 

 without figures it is not possible to determine just what his 

 species is. His description of the pygidium agrees more closely 

 with Whit field 'S' Wisconsin form, than with the original 7. in- 

 signis. 



Kindle's identification of the species from northern Indiana 

 is not entirely satisfactory. Neither his illustration nor his 

 description indicate fully the characters of his specimens; they 

 possess the elongate dorsal furrows of the species terminating 

 in pits, and seem to have the lip-like extension of the anterior 

 margin, but the cephalon is less pointed in front than the Haw- 

 thorn specimens, and the pygidia are more rounded behind, 

 and lack the median ridge. 



Locality. Hawthorn, Illinois. 



*Pal. Ohio, Vol. 1, p. 189. 

 tGeol. Wis., Vol. 4, p. 305. 



l5th Ann. Rep. Geol. and Nat. Hist. Surv. Minn., p. 481: also Geol. Surv. Ohio 

 Vol. 7, p. 525. 



28th Ann. Rep. Dep. Geol. and Nat. Res., Indiana, 1903, p. 479. 



