228 miss j. donald on xhe genus [May 1895, 



preserved on one individual ; the surface is much worn and the apex 

 is broken ; if entire there would probably be four or five more 

 whorls. Its length is 8 millim. 



Locality. Law, Dairy. 



Formation. Lower Limestone Series (d 3 ). 



Section Stegoccelia, Don. 

 Uttrchisonia (Stegoccelia) Smithiana, sp. nov. (PI. X. fig. 3.) 



Shell turreted. rather short, composed of more than five whorls. 

 Whorls angular, slightly concave both above and below. Sinual 

 band situated above the angle, broad, raised above the surface 

 of the whorl, somewhat solid, being very slightly grooved, with a 

 fine thread down the middle. Ornamented by two threads above, 

 just below the suture, and one keel below the sinual band, with 

 four additional keels on the body-whorl and a fine thread between 

 the sinual band and the keel next below. Lines of growth fine and 

 distinct, curving back to the band above and forwards below. 

 Mouth oblong, slightly channelled below, inner lip reflected on the 

 body-whorl. Columella nearly straight. 



This species somewhat resembles M. compacta, Don., 1 but differs in 

 the form of the sinual band and in having more numerous keels on 

 the body-whorl. The structure of the sinual band also distinguishes 

 it from the intermediate specimens of M. variabilis. 



The collection of Mr. J. Smith contains a single specimen of this 

 shell. The apex is broken, leaving five whorls, whose length is 5 

 millim., width about 2\ millim. 



Locality. Law, Dairy. 



Formation. Lower Limestone Series (cZ 3 ). 



Mtjrchisonia (Stegoccelia) variabilis, sp. nov. (PI. IX. figs. 6, 

 7, 11.) 



Shell turriculated, composed of nine or ten whorls. Apex acute. 

 Xucleus consisting of from two to three whorls, smooth, the last 

 sometimes swollen. Whorls angular near the middle or rather 

 below. Ornamentation consisting of a strong keel on the augle with 

 two above and below, and one or two additional keels on the body- 

 whorl, the uppermost keel being generally the finest and occasionally 

 absent. Lines of growth not preserved. Sinual band probably 

 situated above the angle, between the keel on the angle and that 

 next above. Sutures deep. Mouth oblong, slightly channelled 

 below, inner lip spread on the body-whorl. Columella thickened, 

 arched. Umbilicus closed. Base convex. 



There are thirty specimens of this species in the collection of 

 Mr. J. Smith, and they show a considerable variation in the width of 

 the spiral angle, so that if we had the two extremes without the inter- 

 mediate forms we might be led to consider them as distinct species, 



1 ' Descr, of some New Sp. of Cai'b. Gasteropoda,' Quart. Jouni. Greol. Soc. 

 toI. xlv. (1889) p. 624, pi. xx. figs. 9-13. 



