THE NAUTILUS. 27 



cus in differentiating his new species from tricarinata, had he had 

 before him a specimen of lexvisii. Then too, his figure, whatever 

 else may be said of it, was certainly never intended to represent a 

 shell of that form. Say further describes bis species as having the 

 whorls " finely and regularly wrinkled across." An examination of 

 Say's descriptions of other species, especially his earlier ones, will 

 show that he commonly used the terms " wrinkles " and " wrinkled " 

 in the same sense that today we would use stria? and striate. Thus 

 Polygyra albolabris, thyroides. profunda and sayii, Pyramidula soli- 

 taria, Circinaria concava and Bulimulus dealbatus are characterized 

 as " wrinkled." Bulimulus midtilatus is " striated with regular ele- 

 vated lines or wrinkles." And Valvata humeralis is stated to be 

 " wrinkled across or rather with slightly raised lines." 



Taking all these things into consideration, we should say that 

 Say's sincera was a subglobose-conic shell, of about the same size and 

 shape of V. tricarinata, but with a rather larger umbilicus and with 

 accurately rounded, finely and regularly striated whorls. Shells 

 answering very exactly to these requirements were collected by the 

 Michigan Fish Commission in 1894, at High Island Harbor, Beaver 

 Islands, Lake Michigan, and were listed as that species, though with 

 no appreciation of its distinction from lewisii (Bull. Mich. Fish 

 Com. No. 6, 99 ; Naut. IX, 5). And there would seem to be no 

 reasonable objection to these being considered as typical examples of 

 Say's species. 



As shown by the figures (figs. 1-3) the general shape of the shell, 

 with its " accurately rounded " whorls and round, deep umbilicus is 

 in exact accord with the original diagnosis. The surface is sculptured 

 with fine, close, regular, thread-like strias, with a marked tendency 

 in many examples to rise in thin, sharp ribs approximating to those 

 of nylanderi. But in no instance are these more elevated ribs as 

 strongly developed as in that form, nor are they so widely spaced. 

 The specimen figured has 3| whorls and measures : Alt. 4, diam # 

 5 mm. 



Many of the specimens have the apical whorls more or less deeply 

 tinged with dull red, the rest of the shell is of a pale greenish, with 

 the apical whorls nearly white in the unicolored examples. 



There is some slight variation in height and correlated with that, 

 in the width of the umbilicus, but not sufficient to connect them 

 specifically with the widely umbilicated lewisii. 



