THE NATURAL HISTORY SURVEY. 395 



time before his death, were pronounced by him to be vermon- 

 tanum. It is one of the commonest Sphaeria found in the area, 

 ranking next to fabale in this respect. It is easily distinguished 

 from the related species by its triagonal form and less dis- 

 tinctly marked umbones. 



p. 1 13 et al. All references iQsolidulum should be changed 

 to vermontanum. 



p. 114. 

 38. Spharium stamineum Conrad. 



This species is very common in Lilycash Creek, near Joliet, 

 111., where it has been collected by Mr. J. H. Handwerk. The 

 specimens from this locality are very variable, some being typ- 

 ical in form, yellowish in color and with the ends of the shell 

 broadly rounded, while others are very dark horn color, the 

 ends more rounded, and the ventral part more regularly in- 

 flated; the umbones are more coarsely sulcated. Some speci- 

 mens from this locality have a wholly inversed hinge. 5. stria- 

 tinum and S. simile have also been found in large numbers in 

 Lilycash Creek. 



p. 117. After 5. simile add the following: 



151. Sphserium lilycashense Baker. Text figure 137. 



Sphcerium lilycashense BAKER, The Nautilus, Vol. XII, No. 6, p. 65, 

 Oct., 1898. 



Shell: Of good size, inflated, rather solid, although not 

 so solid as either staminium, striatinum or simile, subequilateral, 

 indistinctly quadrangular; umbones slightly elevated, well 

 rounded, a little anterior of the center of the shell, marked 

 by numerous rather heavy ridges, the beaks closely approxi- 

 mate; dorsal and ventral margins slightly curved; anterior end 

 rounded, posterior end very broadly rounded; umbonal slopes 

 very much rounded; surface shining, growth lines numerous, 

 coarse, closely set; color varying from light yellowish horn to 

 rather dark horn, with an occasional zone of yellowish; liga- 

 ment weak, light brownish in color; cardinal teeth small, simi- 

 lar in shape and position to those 'of striatinum; lateral teeth 

 quite solid, double in the right and single in the left valve, 

 short, lamellar, nearly straight, the single left valve teeth much 

 more elevated than the double right valve teeth; muscle scars 

 and pallial line faintly visible; nacre bluish, the portion near 

 the umbones transparent; cavity of the beaks rather deep. 

 Length, 14.00; height, 11.00; breadth, 8.50 mill. 

 13.00; " 10.00; " 8.00 " 

 12.50; " 9.75; " 7.50 " 



