108 IOWA ACADEMY OF SCIENCES. 



former publication, are included. These notes are presented in the follow- 

 ing annotated list: 



Family Strepomatid^. 

 Oenus Ooniobasis. 



O. Uvescens, Menke.— In the former list O. cubicoides, Anth. is reported 

 on the authority of Prof. Witter. Mr. Keyes also reports it*. Since the 

 publication of the name about 100 specimens of a Ooniobasis which was col- 

 lected in the Des Moines river, at Humboldt, by Mr. L. B. Elliott, were 

 received. Most of them agree exactly with the description of O. cubicoides, 

 but a comparison of the entire set with authenticated specimens of O. Uve- 

 scens, Mke. from Michigan, Indiana, and New York leaves no doubt that 

 they are the same. The specimens from Humboldt are, therefore, referred 

 to O. Uvescens, Mke. 



Family RissoiD/E. 

 Oenus Pyrgulopsis. 



P. scalar if ormis. Wolf. — The identity of P. mississippiensis, Call and 

 Pilsbry, reported heretofore, and Wolf's species have already been estab- 

 lished by me.f 



Family Viviparid^. 

 Genus Gampelom,a. 



In the former list three species were admitted: C decisum, Say, C. 

 subsolidum, Anth., and C. rufum. If we accept Call's revision of the genus:j: 

 two other specimens (?) should be admitted, namely C. integrum, Say, and 

 C. obesum, Lewis. I cannot, however, see any valid reason for recognizing 

 all these "species" and feel like exclaiming with Mr Simpson: "Why 

 name anything that has neither beginning nor end?" These shells form a 

 series of which the narrower, more elongated (J. subsolidum and decisum 

 form one extreme, G. integrtim is a form usually intermediate and C. rufum 

 and obesum, proportionately wide forms, represent the other extreme. 

 Extreme, or "type" forms are apparently distinct, it is true, but there is 

 such a gradual transition from one form to the other that the student who 

 would attempt to separate a large number of specimens sootr becomes inex- 

 tricably tangled. In this connection I would speak with the least assurance 

 of C. decisum as it is possible that the Iowa forms which have been vari- 

 ously referred to in this species are merelv variations of G. subsolidum. G. 

 subsolidum and G. obesum connect closely by intermediate forms, and G. 

 integrum cannot be separated from either satisfactorily. 



G. rufum, in its extreme development, seems to be very distinct, but in 

 a large series of the form obtained at Cedar Rapids, where I have collected 

 it in the Cedar river during almost every one of the past eleven years, the 

 pink color of the apex and interior of the aperture and the sculpturing of 

 the surface are by no means the reliable characters which they are repre- 

 sented to be, and the form grades insensibly into C. obesum. It seems that 

 Mr. Binney's disposition of these forms]! is still the best, and that all should 



*An Annotated Catalogue of the Mollusca of Iowa.— Charles R. Keyes, in Bulletin 

 of the Essex Institute, Vol. XX, 1889. 



+Bull. Lab. Nat. Hist. S. Univ. of Iowa, Vol. I, No. 2, June, 1892. 



$0n the Genus Campeloma, ^R. Ellsworth Call— Bull. Wash. Call. Lab. Vol. I. 

 No. 5. 



IILand and. ¥r. Water Shells of iV. Am., part III. 



