448 Roundy — Color Markings of Carboniferous Gastropods. 



widely spaced. Some are persistent, extending from the 

 suture to the dark area on the base, while others are inter- 

 rupted. Often the arrangement consists of alternate persistent 

 stripes with discontinuous stripes, as shown in fig. 5. 



This is probably the first American species to be placed in 

 DeKoninck's genus Glyptobasis.* It has been confused with 

 Holopea proutana in the past, as is shown by a few specimens 

 in Hall's collection being included with that species. How- 

 ever, it is easily distinguished from H. proutana by its stri- 

 ated base and by its somewhat flattened, sides. 



This species is named in honor of Elliott Marshall, who made 

 the collection from Stinesville which furnished practically all 

 the specimens showing coloration, one specimen, however, 

 being noted in the collection from Spergen Hill. 



Locality and horizon. — Spergen limestone, Stinesville, Sper- 

 gen Hill, and Harrodsburg, Indiana. 



Holopea proutana Hall. 



The specific characters of this well-known species require no 

 comment. It is represented in the Stinesville collection by 

 120 specimens, of which 33 show distinct and regular color 

 markings. These markings consist of revolving bands, six in 

 number, of alternating light and dark tints, the first, third, and 

 fifth being light and the second, fourth, and sixth dark. The 

 dark bands may be described as of a grayish brown color and 

 the others as light gray. They are very distinct on the last 

 whorl with regular and well-defined boundaries, but are 

 usually faint or wanting on the spire. Narrow, thread-like 

 lines of color are also sometimes present but their occurrence 

 is sporadic and they may best be considered as modifications of 

 the bands. 



The bands are of nearly equal width; in some specimens the 

 third and fifth are wider, in others the second and fourth, 

 while in still others the fourth is wider than any of the rest. 



The third band, which as stated is light-colored, usually 

 occupies the peripheral zone of the whorls. The fourth band 

 (dark-colored) is probably the most conspicuous one of the 

 body whorl but in the spire it is mostly covered by the overlap 

 of the succeeding volution. 



On the whorls of the spire it is the second band which is 

 most conspicuously seen when it can be seen at all. The fifth 

 and sixth bands are of course completely concealed on the 

 whorls of the spire. 



In 16 specimens there is but little variation from this 



* DeKouinck, L. G., Annates du Mus. Royal d'Histoire Nat. d. Belgique, 

 vol. vi, pt. 3, p. 92, 1881. 



