194 G. LINDSTRÖM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND. 



Subulites brevis 1865. Winchell and Marcey, Fossils of the Niagara Liniestone of Chicago in Mem. 



Boston N. H. Soc, vol. I, 100, pl. II f. 19. 

 1868. Meek and Worthen Geol. Survey of Illinois, III, .362, pl. 5 f. 6. 

 Subulites ventricosus 1868. Hall 20th Rept. N. Y. St. Cab. Revis. Ed., .398 pl. 15 f. 1. 



Shell, short, thick, with five whorls, body whorl in length equal to the other 

 four whorls, with which it forms a small angle. Seen from the side the axis is slightly 

 curved. The aperture is narrow, elongate, inferiorly acuminate, above rounded; lower 

 lip continued downwards in an acuminated point. The outer lip thin and sharp, 

 somewhat inflexed, inner lip involuted, bent in a gentle curve and covered with a thin 

 coat of porcellanous shell matter. The siphonal notch is small, but distinct and di- 

 rected obliquely towards the outer lip. H. 38 mm., bfeadth 20 mm., h. of aperture 

 19 mm., breadth 10 mm. There is commonly only the nucleus left and the few ve- 

 stiges of the shell and its ornamentation show a smooth surface. Through the exte- 

 rior resemblance Avith American specimens, which I owe to the kindness of Messrs S. 

 A. Miller and Worthen, I have thought it most convenient to refer the Swedish spe- 

 cimens to the same species as the American ones. 



It occurs in the soft shale at Hallshuk north and south of Wisby, Gnisvärd, 

 Walve ref, Westergarn, also from Fårö and the canal in Rute. Prof. Cleve found 

 specimens in Häftingsklint. 



2. Subulites ventricosus, var. curvus n. 



Pl. XVIII, fig. 60—61. 



Shell slender, bent in a crescent shaped curve, the body whorl forming wnth the 

 apical ones a larger angle than iu the preceding. Whorls six, elongated, slightly con- 

 vex, smooth, the suture shallow. The aperture is narrow and nearly elliptical, acumi- 

 nated below and widened above, where the sipho is situated. The inferior corner of 

 the outer lip is widened in a downwards directed thorn. H. 33 millim., br. 15 millim. 

 This varietj' which I consider as an evolutional form or mutation of the preceding, 

 has been found only in the upper limestone beds near Wisby at Kålens Qvarn and 

 Kyrkberget and in the limestone of Samsugn. 



It differs from Sub. ventricosus chiefly in the more slender shape which is so 

 much curved. 



3. Subulites attenuatus n. 



Pl. XV fig. 22, 23, 48, pl. XVIII fig. 62. 



Shell elongate, slender, fusiform, with seven whorls, body whorl nearly twice as 

 long as broad, axis of the shell straight, not curved. Surface of the extremely tliin 

 shell smooth, without the least traces of ornamentation preserved on the patches still 

 left. Aperture elongate, narrow, nearly four times as long as broad. Lips thin, lower 

 corner of outer lip prolonged in a little acuminated thorn. Aperture on columellar 



