428 PROCEEDINGS OF THE ACADEMY OP 



Dorsum broad, regularly rounded ; sides gently rounded with only a alight 

 depression near the umbilical center. Septa approximate, thickened at the 

 line of junction with the shell, producing furrows along the septum-lines of 

 the cast. Lobes and saddles strongly pronounced. Dorsal lobe clavate lingui- 

 form, with a long cuspidate acumination reaching as far back as the preceding 

 dorsal saddle ; dorsal saddle linguiform, obtuse, unsymmetrieal, indented on 

 the dorsal side by the broadest part of the dorsal lobe, passing the point of 

 the following lateral lobe ; first lateral lobe profound, rather narrow, extend- 

 ing as far back as the dorsal, sublinguiform, acute ; lateral saddle deep, very 

 broad, somewhat regularly arched to the umbilical point, extending nearly as 

 far forward as the dorsal saddle. Exterior unknown ; surface of cast smooth 



Diameter of cast of last whorl -84 (100) ; axial diameter -38 (46) ; greatest 

 transverse diameter of tube -42 (50) ; distance from axial diameter to dorsum 

 47 (56) ; length of dorsal lobe -21 (25) ; of dorsal saddle -19 (22) ; of latera! 

 lobe -20 (24). 



Locality. Marshall. 



This well-marked species resembles G. rotatorius, de Kon. and G. Lxion, 

 Hall, in the plan of its septa ; but, besides its smaller size, its transverse 

 diameter is proportionally much greater, being to the whorl diameter as 1 : 2 

 instead of 1 : 3 ; and the diameter through the points of the lateral lobes is 

 as 1 : 2J, while in G. rotatorius it is as 1 : 4. The sides of the new species 

 are also more convex. 



Named in honor of its discoverer, Dr. C. Rominger, of Ann Arbor. 



Goniatites Whitei, n. sp. Shell very small, with surfaces regularly convex, 

 a small deep umbilicus and sinuous apertural constrictions. Dorsum rather 

 abruptly rounded, the curvature gradually diminishing on the sides, which 

 are a little appressed ; umbilical boundary rather sharply defined. Apertural 

 constrictions separated about 80 from each other, forming a broad, shallow, 

 ventral sinus across the dorsum, and a broader and shallower one on each 

 side. Surface of shell faintly marked by lines parallel with the apertural 

 constrictions, and in some cases by indications of fine crowded revolving striae. 

 Lobes and saddles strongly pronounced. Dorsal lobe truncately infundibuli- 

 form, minutely bi-denticulate, with the minute circular siphon issuing from 

 between the denticulations ; first lateral lobe acute, infundibuliform, separated 

 from the dorsal by a deep parabolic saddle ; second lateral lobe, which is sep- 

 arated from the first by a broadly parabolic saddle, is broadly infundibuliform, 

 with its right angled apex resting on the brink of the umbilical pit. 



Diameter -35 (100) ; thickness or transverse diameter -21 (60). 



Locality. Union, Branch county, in blue argillaceous shales of the Huron 

 group. 



Named in honor of A. D. White, Esq., its discover. 



Nautilus, Linnreus. Trematodiscus, Meek & Worthen. 



Nautilus (Trematodiscus) strigatus, n. sp. Shell of medium size ; dorsum 

 flattened, broad, equal to the greatest transverse diameter, bounded by a 

 prominent angLe on each side ; lateral surface making a right angle with the 

 dorsal, curving rapidly into the deep broad umbilicus ; dorso-ventral diame- 

 ter of shell equal to one-half the transverse. Surface marked by deep cut 

 longitudinal flutings, of which about nine occupy the latero-umbilical region, 

 and six, less remote, occupy the space on each side from the dorso-lateral 

 angle half way to the middle line of the dorsum, thus leaving a middle belt 

 along- the dorsum equal to one-half its width, destitute of longitudinal 

 grooves. The dorsal grooves nearer the midline become successively fainter, 

 but the last one is well marked. In the bottom of each of these furrows arn 

 about three very fine longitudinal strise. These two sets are crossed by fine, 

 sharp, rather regular raised striae, which curve gently backwards on the sides, 

 while on the dorsal surface they are deflected, at first gradually, then very 



[Sept. 



