348 THE PALEONTOLOGY OF MINNESOTA. 



[Ijingula (Glossina) cleflecta. 



"The most elevated portion is at one-third the length from the beak, but the 

 convexity of the valve is moderate and regular. 



"Dedicated to Mr. W. D. Hurlbut of Rochester, Minnesota, one of the earliest 

 patrons of the Geological and Natural History Survey." 



Recently Mr. W. H. Scofield found two other specimens of this species at the 

 same locality in which the type was discovered. These specimens, however, add 

 nothing to the interior characters, except that, near the anterior portion, the valves 

 are strongly pitted, a feature, moreover, which is visible also on the type specimen. 



L. hurlbuti differs from L. crassa Hall,* the only species with which it need be 

 compared, in being twice the size, and in having strongly elevated and compara- 

 tively widely separated concentric lines of growth. In L. crassa Hall, which also is 

 referable to Phillips's subgenus Glossina, the surface is described as being "appar- 

 ently smooth, but, under a magnifier, exhibiting fine concentric and radiating strise." 



Formation and locality. From the lower portion of the Galena limestone, in the quarries at Man- 

 torville, and at Weisbach's dam near Spring Valley. Minnesota. 



Collectors. N. H. Winchell and W. H. Scofleld. 

 Mus. Reg. Nos. 393, 7674. 



LINGULA (GLOSSINA) DEFLEOTA W. and S. 



PLATE XXIX, FIGS. 15-18. 



1892, April 1.' Lingula (Glossina) deflecta W. and S. American Geologist, vol. ix, p. 284. 



Shell of medium size, subtriangular ; lateral margins diverging more or less 

 rapidly from an acute apex, to the broadly rounded and deflected anterior third. 

 Shell substance thick, and marked by strong, irregular, concentric lines of growth, 

 between which are numerous finer ones. In profile the line of junction of the 

 valves is more or less convex, dorsal! y. Ventral valve flat or slightly concave 

 medially, and strongly convex transversely. On the interior of the ventral valve 

 there is a distinct but slightly elevated median septum, which originates near the 

 apex, and terminates somewhat beyond the center of the valve, in front of which 

 are the small, middle lateral muscular scars. Upon each side of the median sep- 

 tum are the scars of the progressive central muscles, which gradually expand 

 anteriorly, and terminate just above the middle lateral impressions. The vascular 

 trunks bound the limits of the central scars, and meet just in front of the middle 

 lateral impressions, where they are no longer defined. In front of these scars there 

 is a low median elevation, with a broad shallow depression on each side, the latter 

 being anterior to the vascular trunks and slightly pitted. Numerous irregularly 

 radiating obscure lines back of the anterior margin. 



* Pal. New York, vol. i, p. 98, pi. xxx, fig. 8; 1847. 



