FOSSILS OF THE COAL MKASCKKS. (J07 



ib the group for which the name ,sv7//co.v/o//w was propost-d by BRONX. 

 but palaeontologists have generally regarded the type for which that 

 name was proposed as not being sufficiently distinct from Euompliahtx 

 to be retained as a separate genns. 



A >M iciated with the above a single specimen was found of the same 

 si/e. and agreeing very closely with that from which the foregoing de- 

 scription was drawn up, but differing in being proportionally wider, 

 and not so oblique on the periphery, which is also more convex in the 

 middle. The angle of its under side also differs in being a little further 

 in from the outer margin, and directed downward, instead of outward, 

 while its umbilicus is proportionally deeper. This may be a distinct 

 species, but without more specimens for comparison we do not feel will- 

 ing to regard if as being entitled to a separate name. 



These shells, including E. rnyoxm. Hall, and E. cat Hlo ides, Conrad 

 . are related to E. quadrat u*. of McCoy, from the Mountain Lime- 

 stone of Ireland, though sufficiently distinct specifically. At one time 

 we were inclined to think that E. ntgoxH*. Hall, and E. catilloides, Con- 

 rad, together with a few others, should be separated from Euomphalu*, 

 under a distinct generic name ; but after seeing the large species we 

 have here described, which so closely connect these little shells with 

 such forms as E. pemtangtUatttfj and E. catillm, upon which the genus 

 was originally founded, we can no longer doubt that all of these shells 

 really belong to one genus. This series of intermediate forms connect- 

 ing the small, planorbicular species mentioned above, with the typical 

 forms of Eti.nniphnlux. shows clearly that none of the former belong to the 

 articulate genus Spinn-him. as has been thought by some, but that they 

 are really true mollusks. 



1'"* it ion and locality Montgomery county, Illinois. Upper Coal 

 Measures. 



SIKAPAROLLUS (EuoMi'HALUsi srmircosrs. M. and W. 



PI. -29, Fig. 11. 



,'haltu ruffostu, HALL, l$5b. Iowa Geol. Report. Vol. I, Part 2. p. ~ -, PL 29, Fi<:. 14. (not E. 

 rugotus, Sowerliy. 1H9.) 



'lity and position Common in the roof shales above No. S coal, 

 near Springfield. Illinois, and also found more rarely iu the lower part 

 of the Coal Measures. 



