326 SYSTEMATIC PALEONTOLOGY 



The sipho is small and nearly central. The septa are rather shallow, 

 the sutures transverse, averaging 2.50 mm. apart and with no definite 

 relation to the annulations. The latter sometimes being oblique are 

 crossed by the sutures which, however, may occur within a furrow. 



Occurrence. MAETINSBURG SHALE (Sinuites bed). Chambersburg, 

 Pennsylvania. Black River and Trenton of New York and Canada. 



Collection. U. S. National Museum. 



Family TROCHOLITIDAE 



Genus TROGHOLITES Conrad 

 TKOCHOLITES INTEKNISTRIATUS (Whitfield) 



Plate XXXV, Fig. 14 



Lituites internistriatus Whitfield, 1886, Bull. Amer. Mus. Nat. Hist, vol. i, 



p. 332, pi. xxix, figs. 5-8. 

 Trocholites internistriatus Ruedemann, 1906, Bull. New York State Mus., 



90, p. 479, pi. xxiv, fig. 2, text fig. 38. 



Description. Shell of rather small size, being about 50 mm. in diam- 

 eter, and consisting of between two and three volutions. Volutions very 

 slightly compressed laterally, but nearly circular in general outline, with 

 a rounded dorsal margin. Outer surface of volutions obliquely annulated 

 with the annulations best developed on the sides and rounded on the 

 surface; in each case separated by concave interspaces of equal width. 

 The annulations are directed strongly backward from the suture on the 

 side of the shell, where they gradually die out and then become obsolete 

 or nearly so on the dorsum. Shell substance thick, the surface on the 

 undulations and between marked by strong, almost lamellose striae, 

 following the direction of the undulations on the sides of the shell, forming 

 a deep retral sinus on the dorsum indicating a deep sinus in the dorsal 

 lip of the aperture. Interior of the shell as indicated in exfoliated speci- 

 mens marked throughout by very fine, transverse, thread-like striae, 

 directed almost across the tube and numbering about 30 in the space of 

 2.5 mm. Septa about 2.5 mm. apart near the base of the outer chamber 



