IOWA ACADEMY OF SCIENCES. 45 



of the first species. All are represented In our Iowa moUuscan fauna, and all are 

 terrestrial, hence the general result is the same. They are not all reported in the col- 

 lection, hence are not separately listed. A critical review of these and other forms 

 will appear in a monograph of the loess Mollusca. which the author is preparing. 



6. These include S. obli/jua, S. lineata and i». avara. All belong to a division of the 

 genus Swccinea the species of which are terrestrial in habit, and occur living in abua- 

 dance in Iowa and Nebraska to-day. 



The remarks on Pupidce in the preceding foot-note apply equally well to these 

 Stuxinece. 



7. This is Swallow's (i. c ) Amnicoln, lapidaria from Missouri. Todd {I. c, p. 7) also 

 reports it doubtfully from southern Iowa. 



8. These Include L. caperata, L. humilis and probably L. desidiosa. As many, 

 especially youQg specimens, cannot readily be referred t j their respective species, all 

 are here grouped together. A more complete discussion of these forms will appear 

 later. (See foot-note 5 ) 



9. Physa gyrina and P hcterostrophi have both been reported from Missouri by 

 Swallow (I. c.) Our specimens are very young, but probably belong to P. gyrina. 



10. Reported as Physa elongata by Swallow (l. c.) from Missouri. 



11. Doubtfully reported by Todd (L c. p. 7) from southern Iowa, and by Witter (in 

 notes on the Loess) from East Des Moines. 



13. Reported as Plano7-bis armigerus from Missouri by Swallow (I.e.). 



13. Reported as "rare and local" by Professor Witter, U. S. Geol. Sur., Vol. XI, p. 

 471. It may be from modified loess. 



14. Swallow (f. c ) also reports a Cyclas from Missouri. This name was formerly 

 applied to both Pisicimm and SpTicerium. Hambach (Bull. No. 1, Geol. Sur. of Mo., p. 

 83), who practically reproduces Swallow's list, omits this entirely. 



15. In the U. S. Geol Sur , Vol XI, p. 471, McGee reports the following species on 

 authority of Professor Witter: 



Unio ebenus Lea. 

 Unio ligamentinus Lam. 

 Vnio rectus Lam. 

 Margaritana confragosa Say. 



16. From Binney's Terrestrial Air-hreathing Mollusks, Vol. V (except the last 

 species). In most cases these are simply reported as " post-pleiocene," but several a' e 

 specifically reported from Natchez Bluflf. Most of the species belong wholly to the 

 southern fauna, and all are terrestrial. 



Only such " post-pleiocene" species as are not given in Table I are included in 

 Table II. 



17. It is possible that this is P. slrigosa cooperi as given in Table 1. Mr. Binney, the 

 veteran conchologist, at first pronounced our loess specimens P. solitaria, but upon a 

 closer examination of Iowa specimens declared his inability to decide between that 

 species and P. strignsa cooperi. 



18. Reported from the "post-pleiocene" by Binney in Land and Fresh-water Shells 

 of N. Am , part 3, p. 108. The species is strictly terrestrial and is now common in the 

 southern states. 



